BACKGROUND: The prosocial compound ± 3,4-methylenedioxymethamphetamine (MDMA) is an amphetamine derivative that has shown promise as an adjunct to psychotherapy in the treatment of post-traumatic stress disorder. MDMA increases positive responses to social images, and it has been suggested that the ability of MDMA to positively bias social perception may underlie its therapeutic efficacy as a psychotherapy adjunct. However, the effect of the compound on affective responses to positive or negative social feedback has not been tested. AIMS: In this study, we aimed to test the effects of MDMA compared to placebo and the prototypical stimulant, methamphetamine (MA), on responses to positive and negative social feedback. METHODS: This was a double-blind, placebo-controlled, crossover trial (NCT03790618), comparing the effects of two doses of MDMA (0.75 mg/kg, 1.5 mg/kg) to both placebo and MA (20 mg) on responses to a personalized social feedback task, similar to a dating app, in healthy adult volunteers ages 18-40 (N = 36, 18 women, 18 men). RESULTS/OUTCOMES: The high dose of MDMA increased positive affective responses to social feedback. CONCLUSIONS/INTERPRETATIONS: These findings suggest one process by which MDMA may facilitate social connection. Further work is needed to understand how MDMA affects responses to more generalized types of social feedback and to understand these effects in clinical populations.