Rockeymoore Cummings, a policy consultant, cited "personal considerations" in dropping out of the race Friday.
Cummings, 66, the ranking Democrat on the House Oversight and Government Relations committee who is serving his 11th term, spent nearly three months away from Congress after heart surgery last fall.
Rockeymoore Cummings, the second woman and the last of eight candidates to enter the crowded race, launched her campaign three months ago.
"Making a positive and direct contribution to the state of Maryland and to our nation was my greatest motivating factor for stepping into the public arena," Cummings said in a statement. "Unfortunately due to personal considerations, I am suspending my bid for governor of Maryland."
A spokesman for her campaign did not immediately return a call seeking comment.
The announcement comes just weeks before candidates must file fundraising reports, which will provide a strong indication of how well they might fare against the popular and the well-financed governor, Larry Hogan (R), who is seeking a second term.
Rockeymoore Cummings had difficulty getting her campaign off the ground despite a key endorsement from Emily's List, a political action committee that pushes to elect Democratic women who support abortion rights. Before she launched her bid, nine percent of voters in a Goucher Poll taken in September said they would consider voting for her.
Rockeymoore Cummings has worked in politics as a staffer on Capitol Hill and for the Congressional Black Caucus Foundation but was not widely known in state politics. The bid for governor was her first run for public office. As a small-business owner, Rockeymoore focused her campaign on addressing economic inequality. Her decision leaves just one woman, Krishanti Vignarajah, a former policy aide to Michelle Obama, in the governor's race.
"Maya Rockeymoore Cummings is a change agent committed to fighting for working families, and I thank her for entering the race to bring her uplifting and purposeful message to Maryland voters," said Kathleen Matthews, chair of the state Democratic Party.
In a brief statement announcing the decision, Rockeymoore Cummings thanked her supporters andothers she met during the short-lived campaign "who also fervently believe that we can and must do better for the people of Maryland." She said she plans to continue to "advance a diverse, inclusive and thriving economy and society."
In addition to Shea and Vignarajah, the other candidates include Prince George's County Executive Rushern L. Baker III, Baltimore County Executive Kevin Kamenetz, former NAACP president Ben Jealous, State Sen. Richard S. Madaleno Jr., attorney Jim Shea and tech entrepreneur Alec Ross.