List of unnumbered minor planets: 2003 U (0–289)

This is a partial list of unnumbered minor planets for principal provisional designations assigned during 16–31 October 2003. Since this period yielded a high number of provisional discoveries, it is further split into several standalone pages. , a total of 174 bodies remain unnumbered for this period. Objects for this year are listed on the following pages: A–E · F–G · H–L · M–R · Si · Sii · Siii · Siv · T · Ui · Uii · Uiii · Uiv · V · Wi · Wii and X–Y. Also see previous and next year.

U

|- id="2003 UC" bgcolor=#FA8072 | 1 || 2003 UC || MCA || 19.86 || data-sort-value="0.26" | 260 m || multiple || 2003-2025 || 04 Apr 2025 || 50 || align=left | — || |- id="2003 UE" bgcolor=#FFC2E0 | 0 || 2003 UE || AMO || 20.32 || data-sort-value="0.31" | 310 m || multiple || 2003–2021 || 29 Nov 2021 || 149 || align=left | — || |- id="2003 UF" bgcolor=#E9E9E9 | 0 || 2003 UF || MBA-M || 17.8 || 1.2 km || multiple || 2003–2020 || 12 Dec 2020 || 173 || align=left | — || |- id="2003 UM" bgcolor=#FA8072 | 0 || 2003 UM || MCA || 18.4 || data-sort-value="0.62" | 620 m || multiple || 2003–2020 || 22 Jun 2020 || 145 || align=left | — || |- id="2003 UV1" bgcolor=#E9E9E9 | 0 || || MBA-M || 19.0 || data-sort-value="0.67" | 670 m || multiple || 2003–2020 || 08 Nov 2020 || 21 || align=left | Disc.: LPL/Spacewatch IIAdded on 17 June 2021 || |- id="2003 UE2" bgcolor=#d6d6d6 | 0 || || MBA-O || 18.4 || 1.2 km || multiple || 2003–2019 || 03 Dec 2019 || 41 || align=left | — || |- id="2003 UL2" bgcolor=#fefefe | 0 || || MBA-I || 19.03 || data-sort-value="0.46" | 460 m || multiple || 2003–2022 || 06 Jan 2022 || 55 || align=left | Alt.: 2017 QP53 || |- id="2003 UG3" bgcolor=#d6d6d6 | 1 || || MBA-O || 18.0 || 1.4 km || multiple || 2003–2021 || 03 Jan 2021 || 45 || align=left | Alt.: 2014 SP167 || |- id="2003 UM3" bgcolor=#FFC2E0 | 9 || || APO || 28.1 || data-sort-value="0.0085" | 9 m || single || 1 day || 18 Oct 2003 || 12 || align=left | — || |- id="2003 UQ3" bgcolor=#FFC2E0 | 0 || || AMO || 19.6 || data-sort-value="0.43" | 430 m || multiple || 2003–2020 || 07 Dec 2020 || 140 || align=left | — || |- id="2003 UA4" bgcolor=#fefefe | 0 || || MBA-I || 19.0 || data-sort-value="0.47" | 470 m || multiple || 2003–2018 || 11 Nov 2018 || 34 || align=left | — || |- id="2003 UB5" bgcolor=#FFC2E0 | 0 || || AMO || 19.59 || data-sort-value="0.43" | 430 m || multiple || 2003–2021 || 17 Apr 2021 || 345 || align=left | — || |- id="2003 UC5" bgcolor=#FFC2E0 | 0 || || APO || 20.35 || data-sort-value="0.30" | 300 m || multiple || 2003–2021 || 07 Nov 2021 || 99 || align=left | — || |- id="2003 UD5" bgcolor=#FFC2E0 | 1 || || AMO || 23.3 || data-sort-value="0.078" | 78 m || single || 33 days || 20 Nov 2003 || 110 || align=left | — || |- id="2003 UJ5" bgcolor=#E9E9E9 | 0 || || MBA-M || 18.25 || 1.2 km || multiple || 2003–2021 || 16 Jul 2021 || 57 || align=left | — || |- id="2003 UL5" bgcolor=#fefefe | 0 || || HUN || 19.9 || data-sort-value="0.31" | 310 m || multiple || 2003–2018 || 17 May 2018 || 21 || align=left | — || |- id="2003 UQ5" bgcolor=#E9E9E9 | 2 || || MBA-M || 17.5 || 1.8 km || multiple || 2003–2014 || 05 Mar 2014 || 32 || align=left | Alt.: 2014 EL75 || |- id="2003 UR5" bgcolor=#FA8072 | 0 || || MCA || 19.3 || data-sort-value="0.58" | 580 m || multiple || 2003–2020 || 15 Dec 2020 || 77 || align=left | — || |- id="2003 UW5" bgcolor=#FFC2E0 | 6 || || AMO || 24.3 || data-sort-value="0.049" | 49 m || single || 44 days || 01 Dec 2003 || 53 || align=left | — || |- id="2003 UX5" bgcolor=#FFC2E0 | 0 || || APO || 20.29 || data-sort-value="0.31" | 310 m || multiple || 2003–2023 || 19 Mar 2023 || 276 || align=left | Potentially hazardous object || |- id="2003 UD6" bgcolor=#E9E9E9 | 0 || || MBA-M || 17.9 || 1.1 km || multiple || 2003–2019 || 28 May 2019 || 25 || align=left | — || |- id="2003 UE6" bgcolor=#fefefe | 0 || || HUN || 20.12 || data-sort-value="0.28" | 280 m || multiple || 2003–2021 || 27 Jun 2021 || 22 || align=left | Disc.: SpacewatchAdded on 22 July 2020 || |- id="2003 UG7" bgcolor=#FA8072 | 1 || || MCA || 16.9 || 1.2 km || multiple || 2003–2021 || 03 Jan 2021 || 79 || align=left | — || |- id="2003 UZ7" bgcolor=#FA8072 | 2 || || MCA || 20.9 || data-sort-value="0.28" | 280 m || multiple || 2003–2016 || 02 Nov 2016 || 33 || align=left | Alt.: 2016 TG18 || |- id="2003 UE8" bgcolor=#FFC2E0 | 6 || || AMO || 24.9 || data-sort-value="0.037" | 37 m || single || 43 days || 30 Nov 2003 || 36 || align=left | — || |- id="2003 UF8" bgcolor=#E9E9E9 | 0 || || MBA-M || 18.4 || data-sort-value="0.88" | 880 m || multiple || 2003–2021 || 07 Jan 2021 || 73 || align=left | — || |- id="2003 UL9" bgcolor=#FFC2E0 | 7 || || APO || 22.4 || data-sort-value="0.12" | 120 m || single || 6 days || 25 Oct 2003 || 24 || align=left | — || |- id="2003 US9" bgcolor=#FA8072 | 2 || || MCA || 18.5 || data-sort-value="0.59" | 590 m || multiple || 2003–2016 || 13 Mar 2016 || 82 || align=left | — || |- id="2003 UC10" bgcolor=#FFC2E0 | 8 || || APO || 23.9 || data-sort-value="0.059" | 59 m || single || 13 days || 02 Nov 2003 || 29 || align=left | — || |- id="2003 UO12" bgcolor=#FFC2E0 | 0 || || APO || 23.9 || data-sort-value="0.059" | 59 m || multiple || 2003–2018 || 20 Feb 2018 || 195 || align=left | Alt.: 2018 AX11 || |- id="2003 UP12" bgcolor=#FFC2E0 | 7 || || APO || 25.5 || data-sort-value="0.028" | 28 m || single || 5 days || 26 Oct 2003 || 37 || align=left | — || |- id="2003 UQ12" bgcolor=#FFC2E0 | 7 || || APO || 24.9 || data-sort-value="0.037" | 37 m || single || 9 days || 30 Oct 2003 || 40 || align=left | — || |- id="2003 UY12" bgcolor=#FFC2E0 | 1 || || ATE || 22.9 || data-sort-value="0.093" | 93 m || multiple || 2003–2016 || 13 Nov 2016 || 84 || align=left | Alt.: 2003 US12, 2013 UT8 || |- id="2003 UC13" bgcolor=#E9E9E9 | 0 || || MBA-M || 17.90 || 1.1 km || multiple || 2003–2022 || 27 Jan 2022 || 62 || align=left | — || |- id="2003 UZ14" bgcolor=#d6d6d6 | 0 || || MBA-O || 17.43 || 1.1 km || multiple || 2003-2022 || 17 Sep 2022 || 48 || align=left | — || |- id="2003 UL15" bgcolor=#d6d6d6 | 2 || || MBA-O || 17.65 || 1.5 km || multiple || 2003-2020 || 30 May 2020 || 46 || align=left | — || |- id="2003 UV15" bgcolor=#FA8072 | 0 || || MCA || 18.3 || data-sort-value="0.65" | 650 m || multiple || 2003–2011 || 01 Aug 2011 || 49 || align=left | — || |- id="2003 UA17" bgcolor=#d6d6d6 | 2 || || MBA-O || 17.7 || 1.6 km || multiple || 2003–2020 || 15 Oct 2020 || 32 || align=left | Disc.: SpacewatchAdded on 17 January 2021 || |- id="2003 UC17" bgcolor=#E9E9E9 | 1 || || MBA-M || 18.3 || data-sort-value="0.65" | 650 m || multiple || 2003–2019 || 17 Nov 2019 || 27 || align=left | — || |- id="2003 UQ17" bgcolor=#d6d6d6 | 1 || || MBA-O || 18.2 || 1.3 km || multiple || 2003–2019 || 24 Oct 2019 || 31 || align=left | Disc.: SpacewatchAdded on 22 July 2020Alt.: 2014 VH29 || |- id="2003 US17" bgcolor=#d6d6d6 | 0 || || MBA-O || 17.0 || 2.2 km || multiple || 2003–2021 || 09 Jan 2021 || 37 || align=left | Disc.: SpacewatchAdded on 22 July 2020 || |- id="2003 UK18" bgcolor=#fefefe | 0 || || MBA-I || 19.4 || data-sort-value="0.39" | 390 m || multiple || 2003–2020 || 23 Nov 2020 || 40 || align=left | Disc.: SpacewatchAdded on 17 January 2021 || |- id="2003 UW18" bgcolor=#E9E9E9 | 0 || || MBA-M || 17.9 || 1.5 km || multiple || 2001–2017 || 25 Oct 2017 || 37 || align=left | — || |- id="2003 UX18" bgcolor=#fefefe | 1 || || MBA-I || 19.66 || data-sort-value="0.39" | 390 m || multiple || 2003-2025 || 23 Sep 2025 || 44 || align=left | — || |- id="2003 UY19" bgcolor=#FFC2E0 | 1 || || AMO || 18.6 || data-sort-value="0.68" | 680 m || multiple || 2003–2008 || 16 Jan 2008 || 122 || align=left | — || |- id="2003 UA21" bgcolor=#FA8072 | 1 || || MCA || 19.0 || data-sort-value="0.88" | 880 m || multiple || 2003–2017 || 17 Nov 2017 || 32 || align=left | — || |- id="2003 UB22" bgcolor=#FFC2E0 | 8 || || APO || 24.3 || data-sort-value="0.049" | 49 m || single || 7 days || 28 Oct 2003 || 35 || align=left | — || |- id="2003 UC22" bgcolor=#FFC2E0 | 0 || || AMO || 22.03 || data-sort-value="0.14" | 140 m || multiple || 2003-2022 || 19 Nov 2022 || 88 || align=left | — || |- id="2003 UE22" bgcolor=#FFC2E0 | 7 || || AMO || 24.7 || data-sort-value="0.041" | 41 m || single || 13 days || 05 Nov 2003 || 47 || align=left | — || |- id="2003 UG22" bgcolor=#FFC2E0 | 1 || || APO || 21.2 || data-sort-value="0.20" | 200 m || multiple || 2003–2020 || 22 Nov 2020 || 162 || align=left | — || |- id="2003 UL22" bgcolor=#E9E9E9 | 0 || || MBA-M || 18.4 || 1.2 km || multiple || 2003–2021 || 09 Sep 2021 || 54 || align=left | Alt.: 2021 PB64 || |- id="2003 UM22" bgcolor=#d6d6d6 | 1 || || MBA-O || 17.18 || 2.0 km || multiple || 2003–2021 || 27 Nov 2021 || 30 || align=left | — || |- id="2003 UP24" bgcolor=#FFC2E0 | 0 || || AMO || 20.1 || data-sort-value="0.34" | 340 m || multiple || 2003–2013 || 08 Nov 2013 || 95 || align=left | — || |- id="2003 US24" bgcolor=#fefefe | 9 || || MBA-I || 20.1 || data-sort-value="0.28" | 280 m || single || 1 day || 25 Oct 2003 || 9 || align=left | — || |- id="2003 UT24" bgcolor=#FA8072 | – || || MCA || 20.2 || data-sort-value="0.27" | 270 m || single || 20 days || 25 Oct 2003 || 23 || align=left | — || |- id="2003 UO25" bgcolor=#FFC2E0 | 4 || || APO || 22.6 || data-sort-value="0.11" | 110 m || multiple || 2003–2005 || 28 Oct 2005 || 54 || align=left | — || |- id="2003 UP25" bgcolor=#FFC2E0 | 7 || || AMO || 23.3 || data-sort-value="0.078" | 78 m || single || 12 days || 05 Nov 2003 || 56 || align=left | — || |- id="2003 UQ25" bgcolor=#FFC2E0 | 7 || || APO || 24.1 || data-sort-value="0.054" | 54 m || single || 11 days || 04 Nov 2003 || 57 || align=left | — || |- id="2003 UR25" bgcolor=#FFC2E0 | 8 || || APO || 25.5 || data-sort-value="0.028" | 28 m || single || 0 day || 25 Oct 2003 || 18 || align=left | — || |- id="2003 UW26" bgcolor=#FFC2E0 | 0 || || AMO || 19.18 || data-sort-value="0.52" | 520 m || multiple || 2003–2021 || 01 Dec 2021 || 156 || align=left | — || |- id="2003 UX26" bgcolor=#FFC2E0 | 7 || || APO || 24.5 || data-sort-value="0.045" | 45 m || single || 8 days || 01 Nov 2003 || 68 || align=left | — || |- id="2003 UZ26" bgcolor=#d6d6d6 | 0 || || MBA-O || 16.6 || 2.7 km || multiple || 2003–2020 || 16 Nov 2020 || 60 || align=left | Disc.: LPL/Spacewatch IIAdded on 17 January 2021Alt.: 2010 CK207 || |- id="2003 UY27" bgcolor=#FA8072 | 0 || || MCA || 17.7 || 1.2 km || multiple || 2003–2021 || 12 Jan 2021 || 381 || align=left | Alt.: 2003 XB || |- id="2003 UE30" bgcolor=#E9E9E9 | 1 || || MBA-M || 17.9 || data-sort-value="0.78" | 780 m || multiple || 2003–2015 || 10 Sep 2015 || 21 || align=left | Disc.: SpacewatchAdded on 29 January 2022 || |- id="2003 UO30" bgcolor=#fefefe | 1 || || MBA-I || 18.9 || data-sort-value="0.49" | 490 m || multiple || 2003–2018 || 16 Sep 2018 || 24 || align=left | — || |- id="2003 UX30" bgcolor=#fefefe | 2 || || MBA-I || 19.2 || data-sort-value="0.43" | 430 m || multiple || 2003–2020 || 05 Nov 2020 || 42 || align=left | Disc.: SpacewatchAdded on 17 January 2021 || |- id="2003 UB31" bgcolor=#E9E9E9 | 0 || || MBA-M || 18.00 || 1.4 km || multiple || 2003–2021 || 11 Sep 2021 || 35 || align=left | Disc.: SpacewatchAdded on 21 August 2021 || |- id="2003 UD31" bgcolor=#fefefe | 0 || || MBA-I || 19.1 || data-sort-value="0.45" | 450 m || multiple || 2003–2021 || 08 Jun 2021 || 30 || align=left | — || |- id="2003 UF31" bgcolor=#E9E9E9 | 1 || || MBA-M || 18.62 || 1.1 km || multiple || 2003–2021 || 06 Nov 2021 || 45 || align=left | Disc.: SpacewatchAdded on 5 November 2021Alt.: 2012 VX10, 2021 RV78 || |- id="2003 UM31" bgcolor=#d6d6d6 | 2 || || MBA-O || 18.0 || 1.4 km || multiple || 2003–2019 || 27 Sep 2019 || 21 || align=left | Disc.: SpacewatchAdded on 21 August 2021 || |- id="2003 UP32" bgcolor=#d6d6d6 | 1|| || MBA-O || 17.6 || 1.7 km || multiple || 2003–2019 || 19 Nov 2019 || 40 || align=left | Alt.: 2019 TU31 || |- id="2003 UU33" bgcolor=#E9E9E9