He was Opening Day starter again for the 1983 season, going just three innings against the Dodgers while allowing six runs on eight hits in a 16-7 loss. He went 15-14 that year, having a 3.48 ERA while starting a league high 38 games and pitching 263.2 innings. His complete games pitched dropped from 16 to nine as he also led the league in wild pitches with 14 and faced a career-high 1,113 batters. He had 152 strikeouts and 101 walks (both higher from the year before). 1984 began with another Opening Day start for Niekro, his fourth and last in a career. He went seven innings but allowed four runs on seven hits in a 4-2 loss to the Montreal Expos. In his penultimate year with the Astros, he went 16-12 with a 3.04 ERA while once again leading all of baseball in games started with 38, pitching 248.1 innings while striking out 127 batters and walking 89. It was the sixth and final time he faced 1,000 batters.