At the end of the 2004 season, he signed a three-year, $25 million contract as a free agent with Cincinnati. His record in 2005 with Cincinnati was 8–15 with a 6.47 ERA, one of the worst ERA's for a full-time starter in NL history. The following season, Milton lowered his ERA to 5.19 despite giving up 29 home runs in 26 starts. He finished 8–8 in just 26 starts after missing 3 weeks to repair a torn cartilage in his left knee.