Sink said she will not challenge Rep. David Jolly, the Republican who won the seat in the 13th Congressional district in the Tampa Bay area, defeating her by less than 2 percentage points. The special election in March was to replace Rep. Bill Young, a Republican who died in October.
"I was certainly all in for the special election and at this point in time I just made the decision that I did not want to run again," Sink said.
Her decision leaves the Democrats without a declared candidate in a district many observers believe they could win. Sink herself said that about 50,000 more people are expected to vote in November than in the special election, with more independents and young people.
Jolly was one of 12 Republicans in the House to vote against Rep. Paul Ryan's proposed budget.
The Rev. Manuel Sykes, president of the St. Petersburg chapter of the NAACP, has said he is considering a run. Candidates must file for the August primary by May 2.
Sink, a former Florida chief financial officer, lost to Gov. Rick Scott by only 1 percentage point in 2010.
[Tampa Bay Times]
Notable deaths of 2014 [PHOTOS]