The Democratic Congressional Campaign Committee outraised the National Republican Congressional Committee by $680,000 in May.
The DCCC raised $6.68 million last month and had $27.5 million in cash on hand. The NRCC raised $6 million in May and reported $33.8 million in cash on hand.
The official fundraising reports of both committees are due to the Federal Election Commission on Wednesday.
In April, the NRCC outraised the DCCC.