The performance, observer-rated, and participant-rated effects of orally administered placebo, and two benzodiazepines, flunitrazepam (2, 4 and 8 mg/70 kg) and triazolam (0.25, 0.5 and 1 mg/70 kg), were compared in 14 sedative drug abusers using a double-blind crossover design. Both flunitrazepam and triazolam produced dose-related decrements in memory and psychomotor/cognitive performance, and increases in many participant- and observer-rated measures. Effects of flunitrazepam had an earlier onset and a longer duration than those of triazolam. Although there was evidence that the flunitrazepam doses selected for study were somewhat higher overall relative to the selected triazolam doses, analysis of the participant-rated measures collected 24 h after drug administration (next-day) suggests that flunitrazepam may have a greater abuse liability than triazolam when abuse liability is assessed 24 h after drug administration. The highest flunitrazepam dose produced effects that were significantly greater than those of the highest triazolam dose on next-day ratings of good effects, take again, and worth; all tested flunitrazepam doses produced effects greater than any triazolam dose on next-day ratings of liking and take again. The highest flunitrazepam dose, but no triazolam dose, significantly increased the maximum dollar value at which participants chose drug over money in a Drug versus Money Choice Procedure.