The binding properties of three N-modified fluorophenyltropane analogs of cocaine were compared in competition experiments with [3H]cocaine. All three analogs displaced specifically bound [3H]cocaine from caudate-putamen membranes of cynomolgus monkeys with affinities exceeding that of cocaine. The compound with the highest affinity, 2 beta-carbomethoxy-3 beta-(4-fluorophenyl)-N-allyl-nortropane, (N-allyl-CFNT) was about three times more potent than cocaine. N-Allyl-CFNT also had cocaine-like interoceptive effects and was about three times more potent than cocaine in squirrel monkeys trained to discriminate cocaine from vehicle in an operant drug discrimination procedure. The results suggest that N-modified fluorophenyltropane derivatives may be useful precursors for development of pharmacological probes for cocaine receptors.