Introduction Previous studies on the acute effects of MDMA on psychomotor performance and impulsivity showed that MDMA acts as a stimulant. These studies assessed performance during daytime, whereas in real life, dance-attendees leaving a party use the drug during the night. Objectives The present study aimed to assess the effects of nocturnal doses of MDMA on psychomotor performance and impulsivity during the night and after a night of sleep deprivation. Materials and methods Fourteen healthy subjects participated in a double-blind, placebo-controlled, two-way within-subject study. The treatment was MDMA (75 and 50 mg) divided over the evening or double placebo. Psychomotor and impulsivity tasks were conducted four times throughout the evening and night. A vigilance test was conducted once, at 5 A.M., and a sleepiness scale was presented to the subjects ten times throughout the evening and night. Results MDMA impaired tracking performance in a simple tracking task. Divided attention task performance was also impaired as indicated by a decrease in secondary task performance under the influence of MDMA compared with placebo. MDMA did not affect impulsivity measures. Vigilance performance decreased as a function of time on task, but this decrement was less during MDMA treatment compared to placebo. After the administration of MDMA, the sleepiness scale scores were lower during the night when compared with placebo. This difference between MDMA and placebo disappeared in the morning. Conclusion It is concluded that nocturnal doses of MDMA may produce impairments of tracking performance and divided attention throughout the night that are additive to performance impairment produced by sleep loss.