During a radio appearance on WBAL, Franchot said the map has "embarrassed our state" and called for future redistricting plans to be developed by a bipartisan commission instead of legislators and the governor.
The congressional map, which the courts have upheld even though some judges criticized it as an obvious case of gerrymandering, was petitioned to referendum through the efforts of mostly Republican activists.
The map was drawn to give Democrats an advantage in seven of the state's eight congressional districts. They currently hold six seats. Much of the criticism revolves around the shape of the Third District, which sprawls from Baltimore County around the city and out toward Annapolis and Montgomery County.
Franchot, who has increasingly steered a course independent of O'Malley as he looks toward a possible run for governor in 2014, charged that Democratic leaders were "driven by partisan motives when coming up with the proposed map and not by the public interest."
The comptroller pointed to a recent study finding that the redistricting gives Maryland the least compact congressional districts in the country. He becomes the latest in a series of Democrats to speak out against the map.
“I am a Democrat, and I like to win elections as much of the next guy -- but not by fixing the outcome and not by compromising our state’s reputation by making a mockery of the electoral process,” Franchot said.
The comptroller also opposes another referendum question, also backed by O'Malley and legislative leaders, that would expand gambling in Maryland.