The U.S. Federal Communications Commission (FCC) said it would host the files on its website, allowing people to easily track information about their local TV stations.
Spending on TV ads is forecast to reach historic levels in 2012 ahead of the U.S. presidential election, as candidates blanket airwaves with commercials promoting their virtues or bashing their opponents.
The flood of political money in part reflects a response to a landmark 2010 Supreme Court ruling that ended most restrictions on political donations from corporations and unions.
The ruling sparked the creation of "Super PACs", or political action committees, that have focused almost exclusively on spending tens of millions of dollars on ads.
But finding data on who spent what, and where, is a tricky endeavor. TV stations have been making these records public since 1938, as well as information on other community-related issues like children's programming.
But the records are kept on paper, in filing cabinets directly at stations' offices. Driving to each station and making copies can take hours, and relying on media analysis companies that aggregate the data is often expensive.
"What this proposal is about is taking that paper file and catching it up with the 21st century," an FCC official said.
Initially, the rule will only apply to affiliates of the four biggest TV broadcasters in the top 50 media markets.
The four biggest broadcasters are ABC, operated by Disney Co, CBS Corp, News Corp's Fox, and NBC, controlled by Comcast Corp.
In all, these top 200 stations represent about 60 percent of the money spent on political TV ads in an election year, the FCC said.
Smaller stations would have another two years to begin complying with the rule. The FCC said it would cost about $1,000 for stations to begin uploading large paper files.
FCC Chairman Julius Genachowski and the full Commission must still sign off on the proposal at a rule-making session at the end of April, after which it must be approved by the White House Office of Management and Budget.
However, the FCC said it expects the requirement to go into effect before the presidential election in November.
(Reporting by Anna Yukhananov; Editing by Lisa Shumaker)