(BALTIMORE)- The longest serving woman in the history of the united states congress will not seek re-election.

Maryland Democrat Barbara Mikulski will not seek a sixth term in the senate in 2016.

She acknowledged it was a hard decision to make. But wanted to focus on her senate work, and not raising money for another campaign.

Mikulski joined the senate in 1987 after serving 10 years in the house of representatives.

The senator has long been known for her blunt advocacy for her causes, including equal protections for women under federal law.

She's helped pave the way for the current record number of women - 20- who serve in the senate.

The 78 year old intends to serve out the remainder of her term.