This comes following a horrendous 7-18 start in which the Brewers have fallen far into the depths of the National League. They are already 11 1/2 games out of the National League Central and 6 1/2 out of the National League Wild Card race.
The 58-year-old has been managing the Brewers since 2011 and had led them to a 341-331 record in that time.
Roenicke led the Brewers to the postseason in his first year at the helm in 2011, as the team went 96-66 en route to the NL Central crown. They were eliminated by the Cardinals in the National League Championship series.
On March 22, 2014, the Brewers announced that they had picked up Roenicke's club option for 2015 and added a club option for 2016. He still could have been relieved of his duties following this season.
"This has been a difficult start to the season, something that we certainly didn't anticipate," Brewers president of baseball operations Doug Melvin said in a press release. "Over roughly the last 100 games, we have not performed at the level that we should. It's all about wins and losses, and after the first month of play this year we didn't see the progress and improvement we had hoped for. We appreciate all that Ron has done for our organization, and he has handled his duties with great professionalism and dedication. The reasons for our disappointing start are many, but we determined that it's in the best interests of the club to make this move."