Assessed the factor structure of the Young Mania Rating Scale (YMRS). Youths presenting to a research program specializing in the pharmacological treatment of mood and disruptive behavioral disorders (N = 612) were administered a semistructured diagnostic interview. Based on the interview, youths were placed into diagnostic groups. Highly trained raters completed the YMRS for each youth. YMRS ratings were internally consistent (alpha = .91), and exploratory and confirmatory factor analyses yielded a 1-factor solution for boys and girls in both young (5 to 11 years) and older (12 to 17 years) subsamples. However, the young male group showed higher scores on several items as well as the total YMRS score. Results suggest that the YMRS total score can be meaningfully interpreted in child and adolescent samples.