Florida Governor Rick Scott, a Republican who campaigned on a promise to expand drug testing, said he would appeal the ruling.

The law took effect in July 2011 and required parents to undergo and pay for urine tests for illegal drugs when they applied for Temporary Assistance for Needy Families, a federal-state program that helps poor people with children pay for food, shelter and necessities.

The testing fee of $25 to $45 was to be repaid by the state if the test came back negative, but applicants who tested positive would have been barred from receiving benefits for a year.