Pittsburgh City Councilman Bruce Kraus planned to introduce a bill requiring companies that sign contracts worth $250,000 or more with the city to provide same-sex domestic partner benefits to their employees.
The city has provided such benefits to its own employees for years, in a policy that was upheld by a state Supreme Court decision in 2004.
Philadelphia passed a similar bill in November 2011.
Kraus said if Pittsburgh follows suit it would be the 13th city in the United States to offer such benefits.
Kraus planned to introduce the bill at council's regular meeting on Wednesday.