They've spent almost $46 million on Google ads over the last 30 days, according to the search engine's data.
The Congressional Leadership Fund, a super PAC that backs House Republicans, has spent $1.32 million over the past month on Google ads.
Democrats have jumped in with spending millions on Google ads over the past four weeks, records show.
The Democratic Senatorial Campaign Committee, a campaign arm for Senate Democrats, has spent just over $1 million in Google ads during that time frame.
The Democratic Congressional Campaign Committee, which acts as the campaign arm for House Democrats, has spent an almost equal amount on Google ads.