The Republican Senatorial Campaign Committee raised $1.5 million in the first month of the 2014 cycle, bringing in $2.7 million less than the Democratic Senatorial Campaign Committee in January.
The Republican committee spent more than $1.6 million in the month of January, and still has $10 million in debt to pay down.
Earlier this week, the DSCC announced it raised a record-breaking $4.2 million in January.
The DSCC had slightly more than $16 million in debt to pay down at the end of December. Its debt as of January 31 was not immediately available.
January was a month of high staff turnover for the NRSC, which hired nearly all new staffers for its political and communications team, promoting only one person internally.
An aide close to the committee points out the NRSC's fundraising lag is similar to what it experienced in January of 2009. The committee ultimately closed the fundraising gap with the DSCC from $70 million in the 2008 cycle to $12 million in the 2012 cycle.
Republicans need to net six seats to take back the Senate, and they've expressed optimism about their chances because of the number of incumbent Democrats up for reelection, particuarly in red-leaning states.
But January's fundraising numbers could dampen that optimism, and will at the very least increase pressure on NRSC Chairman Jerry Moran (R-Kan.) and Vice Chairman of Finance Rob Portman (R-Ohio) to reach out to donors.
NRSC Communications Director Brad Dayspring dismissed the discrepancy in funds, noting that Democrats may need to spend resources on primary battles in New Jersey and Massachusetts.
"Democrats will need every one of those dollars to deal with ugly primary battles in Massachusetts and New Jersey, so it's no wonder they are telling donors that [Democratic Congressional Campaign Committee Chairman] Steve Israel and the DCCC won't win the House," he said.
Republicans, too, may need to jump into Senate primary battles in states like Iowa and Georgia, where early fights between grassroots-backed and establishment-preferred candidates are beginning to brew.
The House Democrats' campaign group outraised its Republican counterpart in January, bringing in $6.1 million, more than the $4.4 million raised by the National Republican Congressional Committee (NRCC) over the same span.
The DCCC now has $4.6 million cash on hand, while the NRCC has $2.8 million cash on hand.