The measure passed the state Senate 26-11 Thursday, The Miami Herald reported, following 78-38 approval by the House in April. Gov. Rick Scott has made it a priority.
"It's fair to taxpayers," the governor said after the vote. "They're paying the bill. And they're often drug screened for their jobs. On top of that, it's good for families. It creates another reason why people will think again before using drugs."
Scott earlier issued an executive order requiring random drug testing of state employees.
The bill makes all adult recipients of federal Temporary Assistance for Needy Families benefits pay for the tests, which usually cost about $35, but those who pass will be reimbursed.
Recipients who test positive for any illicit substances -- after disclosing all prescriptions they take -- will lose benefits for a year. A second failed test will cost them benefits for three years. Parents will have to designate another adult to collect benefits for their children.
The measure provides no funds for drug treatment.