The Astros are hefty favorites in the 2019 World Series, entering Sunday morning -235 to beat the Nationals, according to ESPN's David Purdum.
Washington is +195 to win its first World Series in franchise history.
Houston enters Game 1 on Monday night as the largest World Series favorite since the 2004 Red Sox. Boston entered the series at -240 before sweeping the Rockies for its second title in four years.
The Astros were underdogs in the 2017 World Series at +140. They defeated the favored Dodgers in seven games, winning Game 7 in Los Angeles for the franchise's first championship.
Houston will host Game 1 of the World Series on Sunday. First pitch from Minute Maid Park is slated for 8:08 p.m. ET.