“In some states, they're so far in the past they're even pushing laws to legalize segregation based on sexual orientation,” said Obama in an address to the Democratic National Convention winter meeting in Washington.
“As Democrats, we've let the other side define the word 'freedom' for too long,” he added.
Obama's comments were likely a reference to a recent Arizona bill that would have allowed businesses to refuse service to gay customers.
Supporters said the bill would protect the religious freedom of business owners, but the measure invited harsh criticism from many major companies, including Major League Baseball and Delta Air Lines.
Both of the state’s Republican senators urged Gov. Jan Brewer, R-Ariz., to reject the bill.
Brewer on Wednesday vetoed the bill, saying that “religious liberty is a core American and Arizona value [and] so is non-discrimination.”