The announcement was made Sunday by Astros President of Baseball Operations and General Manager Jeff Luhnow.
"Justin Verlander is one of the elite pitchers in baseball," said Luhnow. "His late-season arrival in 2017 helped the Astros deliver its first ever championship to the city of Houston. Our fans share in my excitement that Justin will be in an Astros uniform for at least three more years."
The agreement will keep the right-hander, who was entering the last year of his contract, in Houston through the 2021 season.
The 36-year-old Verlander was traded from Detroit to Houston on Aug. 31, 2017, and helped the Astros win their first World Series that season. The 2011 American League MVP and Cy Young Award winner finished second in Cy Young voting last season after going 16-9 with a 2.52 ERA in 34 starts. He pitched 214 innings and his 290 strikeouts led the AL.
He led all Major League pitchers in WHIP with an 0.90 clip, which marked the third-lowest number for an AL starter in the last 50 seasons (min. 175 IP). Additionally, Verlander led the AL in pitching WAR (6.8), strikeouts (290), opponent on-base percentage (.242), strikeout to walk ratio (7.78) and road wins (12-2), and was second in innings pitched (214.0). He also ranked third in ERA (2.52) and opponent batting average (.200).
He enters the 2019 season as the Astros Opening Day starter, which will be his 11th Opening Day assignment, his second consecutive with the Astros. In Major League history, only 14 pitchers have made 11 Opening Day starts, including nine Hall of Famers.
Verlander is one of the greatest postseason pitchers of all-time, having gone 13-7 (.650) with a 3.19 ERA (54ER/152.1IP) and 167 strikeouts in 25 career postseason appearances (24 starts). He ranks fourth in postseason wins and strikeouts all-time in MLB history.