The House bill passed 50-24, while the Senate bill passed 28-6.
The Providence Journal reported possession of an ounce or less would carry a $150 fine. However, three violations within an 18-month period would result in a misdemeanor charge carrying a larger fine or possible prison time.
It wasn't known whether Gov. Lincoln Chafee, a Republican, would sign or veto the legislation, which was passed by the two Democrat-controlled bodies Tuesday.