A financial disclosure form filed with the Federal Election Commission Thursday indicated the Adelsons' contribution helped Restore Our Future raised more than $20 million during the first half of October, CNN reported.
As of Oct. 17, Restore Our Future had more than $36 million cash on hand while spending $12 million.
The FEC form indicated donations so far in October nearly matched the amounts the super PAC raised in August and September combined, CNN said.
The Adelsons' $10 million contribution brings the couple's total donation to Restore Our Future to $20 million.
They rank as the top donors to outside political groups, the non-partisan Center for Responsive Politics said.
The latest donation means the couple gave at least $61 million this campaign cycle to organizations that are required to disclose donors -- super PACs, campaign committees and candidates.
Adelson, who operates casinos in Nevada and overseas, had backed former House Speaker Newt Gingrich's bid during the Republican primaries and was reluctant to support Romney once Gingrich left the race.