Both Senate Majority Leader Harry Reid, D-Nev., and House Minority Leader Nancy Pelosi, D-Calif., have signed off on the agreement, CBS News reported.
The Senate was expected to vote Monday night.
The House of Representatives would not vote until Tuesday at the earliest, technically sending the country over the cliff. However, assuming the deal passed through Congress, the agreement was expected to be retroactive to midnight Jan. 1.
According to CBS News, negotiators had settled their differences on tax cuts and estate taxes.
The network is reporting the deal raise tax rates on households making more than $450,000 a year and individuals making more than $400,000 annually.
An agreement had also been reached on the estate tax, which was set to jump from 35-percent to 55-percent. The compromise rate will reportedly be 40-percent, with the first $5 million exempt from being taxed.
Republicans and Democrats remained divided over spending cuts.
The agreement would delay automatic spending cuts for two months, setting up another — smaller — fiscal cliff, while allowing Congress and the White House time to come up with a larger deal on spending cuts.