We investigated the effects of emotion perception training on depressive symptoms and mood in young adults reporting high levels of depressive symptoms (trial registration: ISRCTN02532638). Participants were randomised to an intervention procedure designed to increase the perception of happiness over sadness in ambiguous facial expressions or a control procedure, and completed self-report measures of depressive symptoms and mood. Those in the intervention condition had lower depressive symptoms and negative mood at 2-week follow-up, but there was no statistical evidence for a difference. There was some evidence for increased positive mood. Modification of emotional perception may lead to an increase in positive affect.