A source told Fox News Abercrombie is resigning so he can focus on running for governor.
In a written statement, the Hawaii congressman said the effective date of his resignation will be announced soon, and that it was a difficult choice.
"This is an extremely difficult decision for me, but I must do this to continue with the direction I've chosen for the future. Accordingly, I've concluded that I must resign my congressional seat and allow someone to be elected who will carry on the work of this office," he said.
Abercrombie has held the seat since 1991. The announcement comes after Baird, a six-term congressman from Washington state, caught political analysts by surprise with his announced retirement.
So far this year, the number of announced retirements in both chambers is still higher among Republicans.
In the Senate, three Democrats have announced they're retiring. In the House, 10 Democrats including Abercrombie are leaving.
Six Republicans in the Senate and 12 Republicans in the House are on their way out.