The reinforcing properties of amfonelic acid, a nonamphetamine psychostimulant, were evaluated in an intravenous self-administration paradigm. Rats were trained to self-administer cocaine (0.5-3.0 mg/kg/infusion) on a fixed-ratio 10 schedule of reinforcement via surgically implanted intravenous catheters during daily 4-hr sessions. Substitution of amfonelic acid (0.0625-0.250 mg/kg/infusion) reliably maintained self-administration in a dose-dependent manner. These data indicate that amfonelic acid can act as a reinforcer in rats, and further suggest that amfonelic acid may have abuse potential in humans.