Sen. Mitch McConnell's (R-Ky.) primary challenger had about $165,000 cash on hand at the close of September.
He received contributions from more than 2,000 donors and noted his fundraising total put him on track to match what Sen. Marco Rubio (R-Fla.), another conservative who orchestrated an insurgent win, raised at the same point in his campaign.
"I am extremely encouraged by the support we have received at every turn in the last couple months and am excited to see our momentum growing," Bevin said.
But McConnell, considered by Democrats one of the most vulnerable Republican incumbents up for reelection in 2014, heavily outraised Bevin, bringing in $2.27 million during the July-September period.
His campaign said he drew donations from nearly 6,000 individual donors and now has $10 million cash in the bank.