The 1999 Houston Astros season was the 38th season for the Major League Baseball (MLB) franchise located in Houston, Texas, their 35th as the Astros, 38th in the National League (NL), sixth in the NL Central division, and 35th and final season at The Astrodome. The Astros entered the season as two-time defending NL Central champions with a 102–60 record, setting a then-club record for wins, as well their first-ever 100-win season. However, the Astros' season ended in a 3-games-to-1 defeat by the San Diego Padres in the National League Division Series (NLDS), also the NL pennant winners.

On April 6, pitcher Shane Reynolds made his fourth consecutive Opening Day start for the Astros, who hosted the Chicago Cubs and won, 4–2. In the amateur draft, the Astros' first round selection was outfielder Mike Rosamond at 42nd overall.

Four Astros represented the club, playing for the National League at the MLB All-Star Game: first baseman Jeff Bagwell, and pitchers Mike Hampton, José Lima, and Billy Wagner. This was the fourth All-Star appearance for Bagwell, and first for each of Hampton, Lima and Wagner. Former pitcher Nolan Ryan was inducted into the Baseball Hall of Fame. Ryan spent nine of his 27 MLB seasons with Houston, from 1980 to 1988. Following the season, Ryan was also announced as a selectee to the MLB All-Century Team.

Bagwell tied the Major League record by producing a fourth successive campaigns of each of 100 runs scored, 30 doubles, 30 home runs, 100 runs batted in (RBI) and 100 base on balls (BB), equaling Lou Gehrig. With 30 stolen bases, Bagwell also entered the 30–30 club for the second time in his career.

The Astros won their third consecutive NL Central division title on October 3, the final day of playing regular season games in The Astrodome before a sellout crowd. Fans broke the franchise attendance record for a second consecutive season at over 2.7 million. For the first time in franchise history, Houston claimed three consecutive division titles while qualifying for the playoffs in three straight seasons. This was the Astros' sixth division title and sixth playoff appearance overall. However, their campaign ended in a 3-games-to-1 defeat by the Atlanta Braves in that year's NLDS. It was Houston's third consecutive NLDS loss, and the second in three seasons to Atlanta, who ended their season as the NL pennant winners.

Following the season, Hampton, the NL leader in wins (22) and third-place finisher in earned run average (2.90 ERA), was recognized with the Players Choice Award for NL Outstanding Pitcher and as The Sporting News NL Pitcher of the Year, Wagner won the Rolaids Relief Man Award, and Bagwell and Hampton won Silver Slugger Awards.

The Astros relocated the following season to Enron Field, later rebranded as Minute Maid Park, also in downtown Houston.

Offseason The Astros concluded the 1998 campaign as National League (NL) Central division champions with a record, the first 100-win season in franchise history. It was their second consecutive division title and fifth overall in franchise history. The Astros' campaign ended in a three-games-to-one defeat by the San Diego Padres in the best-of-five National League Division Series (NLDS). The Astros established a then-club record with 166 home runs. Craig Biggio became the first, and so far only, Major Leaguer to amass 200 hits, 50 doubles, 20 home runs, and 50 stolen bases all within the same season. Randy Johnson became the seventh pitcher since 1900 to amass multiple 300-strikeout seasons.

Outfielder Moisés Alou missed the entire 1999 campaign due to a knee injury.

November 17, 1998: Ken Caminiti was signed as a free agent by the Astros. December 9, 1999: Signed Craig Biggio to a 4-year extension for $28 million. January 19, 1999: Ryan Thompson was signed as a free agent by the Astros. January 21, 1999: Alex Diaz was signed as a free agent by the Astros.

Regular season

New stadium

In 1999, the Astros played their final season in the Astrodome as their new stadium was being prepared for play to begin in the 2000 season. The ballpark was first named as Enron Field on April 9, 1999, with naming rights sold to the Houston energy and financial trading company in a 30-year, $100 million deal. Astros management faced a public relations nightmare when the energy corporation went bankrupt in the midst of one of the biggest corporate scandals in American history in 2001, and they bought back the remainder of Enron's thirty years of naming rights for $2.1 million, renaming the ballpark as Astros Field on February 7, 2002. The field was unofficially known as "The Field Formerly Known As Enron" by fans and critics alike, in the wake of the Enron scandal. On June 5, 2002, Houston-based Minute Maid, the fruit-juice subsidiary of Coca-Cola, acquired the naming rights to the stadium for 28 years at a price exceeding $100 million.

Based on its downtown location next to the old Union Station buildings, one of the suggested names (and nicknames) is the Ballpark at Union Station, or the BUS. During its days as Enron Field, it was also dubbed "Ten-Run" or "Home Run" Field due to its cozy left-field dimensions. In keeping with this theme while paying homage to its current sponsor, the nickname "The Juice Box" is colloquially used today.

Summary April + Opening Day starting lineup Player Position 7 Craig Biggio Second baseman 14 Derek Bell Right fielder 5 Jeff Bagwell First baseman 11 Ken Caminiti Third baseman 3 Carl Everett Center fielder 15 Richard Hidalgo Left fielder 20 Tony Eusebio Catcher 12 Ricky Gutiérrez Shortstop 37 Shane Reynolds Pitcher Venue: Astrodome • Final: Houston 4, Chicago 2 Sources:

The Astros hosted the Chicago Cubs for Opening Day, April 6. As part of the festivities to commemorate the final Opening Day at the Astrodome, former astronaut Neil Armstrong spun the ceremonial first pitch. This was also Chicago's first Opening Day in Houston since the Colt .45s' franchise Inauguration Day, April 10, 1962, during which the Colts triumphed, 11–2. Armstrong was flanked by 70 astronauts on either side of the infield, and delivered the pitch to Craig Biggio. Shane Reynolds made his fourth consecutive Opening Day start opposite the Cubs' Steve Trachsel. In the second inning, Mark Grace homered off Reynolds for his first of three hits and early 1–0 Cubs' lead. In the bottom of the inning, Tony Eusebio doubled and scored on a single by Reynolds. In the bottom of the fourth inning, Carl Everett and Richard Hidalgo went deep to give the Astros a 3–2 lead. In the fifth, Everett lined a single to plate Jeff Bagwell for a 4–2 Astros lead and the final tally of the contest. Reynolds breezed through six innings on 75 pitches, whiffing seven. Scott Elarton relieved and spun two shutout frames. Billy Wagner fanned Benito Santiago and José Hernández to polish off the triumph for the save and the win for Reynolds. This defeat dropped the Cubs' all-time record at the Astrodome to .

On the 35th and final anniversary of the opening of the Astrodome, April 9, 1965, Tim Bogar singled home Richard Hidalgo for the winning run to defeat the Milwaukee Brewers, 3–2. Starting pitcher Sean Bergman homered but it was Scott Elarton who notched the victory in relief.

On April 11, Craig Biggio scored his 1,000th run along with two hits to lead a 5–2 win over the Brewers. Shane Reynolds was the winning pitcher.

On April 21, Jeff Bagwell hit three home runs in a 10–3 win against the Chicago Cubs at Wrigley Field, his second career three-home run game. The second home run surpassed Jimmy Wynn as the Astros' all-time home run leader at 224, while his six runs batted in (RBI) tied a career-high. Bagwell joined Glenn Davis as Astros with multiple three-home run games (September 10, 1987, and June 1, 1990).

Run-scoring record at the Astrodome Houston staged an offensive onslaught on May 11 in a record-breaking performance, routing the Pittsburgh Pirates 19–8 at the Astrodome. The 19 runs—all arriving without the benefit of a home run—broke a club record, while the lineup combined to scorch 10 doubles, also a club record. Each of Jeff Bagwell, Richard Hidalgo and Paul Bako doubled twice. Carl Everett collected 5 RBI, and Bagwell and Ken Caminiti both added four. Hence, as this was the final season of baseball at the Astrodome, these feats would remain permanent team records at the venue.

The 19 runs matched a 1995 explosion against the Chicago Cubs for the club record for runs, which stood until the 2015 season. Bagwell reached base five times via the two doubles and drawing three bases on balls while scoring four times. Sean Bergman was the winning pitcher after having allowing 11 hits and 6 runs over 5 innings. The doubles tally stood as a club until another banner offensive performance on September 8, 2019, when Houston collected 11 doubles en route to defeating the Seattle Mariners, 21–1. Everett tied his career high in RBI.

Rest of May On May 14, Carl Everett tied his career high with four hits.

During a 10–5 win over the San Francisco Giants on May 15, second baseman Craig Biggio powered a 4-for-4 performance, including a three-run home run. Bagwell also slugged a three-run home run in the effort.

Everett manufactured 5 successive multi-hit contests and at least one RBI prior to being named NL Player of the Week on May 16. Houston won all five contests as Everett batted .609 (14-for-23), scoring seven runs, and driving in eight.

June—July Bagwell connected for another three-home run game on June 9 against the Chicago White Sox. He was also a grand slam short of hitting for the "home run cycle," with a solo home run, a three-run home run, and a two-run home run, respectively. The two three-home run games made him the only player to accomplish this feat at two different stadiums in Chicago in the same season. Hence, Bagwell became the first Astro with three such games, breaking a tie with Glenn Davis.

On June 13, manager Larry Dierker collapsed in the dugout mid-game versus the San Diego Padres due to a grand mal seizure. He was hospitalized and required brain surgery, but recovered well to miss just 27 games. The game was suspended with Houston leading, 4–0. During the bottom of the sixth inning, Derek Bell crushed the only grand slam of his career to give Houston the lead. In spite of losing Dierker, two other coaches to lengthy absences, and 14 players to the disabled list (DL), the Astros kept the competitive momentum going throughout the season.

Astros general manager Gerry Hunsicker promoted bench coach Matt Galante to serve as interim manager of the Astros in Dierker's stead. Galante, who had been in the organization since 1980 and was bench coach for one year, led the team to a performance result of . It was during this time that the team absorbed the absences of other coaching staff members on medical leave. First base coach José Cruz was on leave after an irregular heart beat. Hitting coach Tommy McCraw underwent treatment for prostate cancer.

MLB All-Star Game Home Run Derby: Jeff Bagwell—Round 1: 5 / Round 2: 1 / Total: 6 (4th place) • Winner: Ken Griffey Jr. (SEA)—Total:16

Four Astros selected to fortify the National League roster at the MLB All-Star Game, hosted at Fenway Park in Boston. It was the fourth selection for Bagwell, who became the first Astro to make the starting lineup as the designated hitter, and first for each of the pitchers Mike Hampton, José Lima, and Billy Wagner. Bagwell collected a single off David Cone in three at bats, while Lima (1 inning pitched), Hampton (), and Wagner () each tossed a scoreless outing. However, the American League (AL) triumphed, 4–1.

July, post-All-Star break