Cognitive impairments in multiple sclerosis (MS) extend to tasks demanding prospective memory (PM): remembering to perform an intended act during ongoing activity. This study investigated whether emotional content influenced the effects of MS on PM, following evidence that emotional valence can influence other aspects of memory. Thirty participants with MS were compared to 30 controls on a PM task, Virtual Week, in which emotion was manipulated. People with MS showed a consistent deficit in PM performance across manipulations of task and valence. Results indicated that emotionally positive tasks improved the PM performance of MS participants, with implications for rehabilitation.