The law would say that anyone with a contract worth more than $25,000 is barred from giving political money to the official who awarded the contract.
State Comptroller Dan Hynes and several lawmakers say that would help erase the perception that people can't win state contracts without giving money to politicians.
Even without a new law in place, Hynes has issued an executive order adopting the restrictions for his own office.
He said Friday that most of the other statewide officials support the legislation, but Gov. Rod Blagojevich is still reviewing the idea.
The governor has awarded contracts to many campaign donors.