Social motivation deficit theories suggest that children with autism do not properly anticipate and appreciate the pleasure of social stimuli. In this study, we investigated event-related brain potentials evoked by cues that triggered social versus monetary reward anticipation in children with autism. Children with autism showed attenuated P3 activity in response to cues associated with a timely reaction to obtain a reward, irrespective of reward type. We attribute this atypical P3 activity in response to reward cues as reflective of diminished motivated attention to reward signals, a possible contributor to reduced social motivation in autism. Thus, our findings suggest a general reward processing deficit rather than a specific social reward dysfunction in autism.