The present study comprised two meta-analyses of published studies that used the Profile of Mood States (POMS) to investigate relationships between mood and athletic achievement (n = 13) and between mood and performance outcome (n = 16). Results showed that effect sizes (ESs) for the level of achievement metaanalysis were minimal (Weighted Mean ES = .10, SD = .07), a finding consistent with a previous meta-analysis by Rowley, Landers, Kyllo, and Etnier (1995). Larger effects were found for the performance outcome meta-analysis (Weighted Mean ES = .31, SD = .12). Effects were moderate for vigor, confusion, and depression, small for anger and tension, and very small for fatigue. All effects were in the direction predicted by Morgan's (1985) Mental Health Model. Effects were larger in sports of short duration, in sports involving open skills, and where performance was judged using self-referenced criteria. Findings suggest that the POMS has utility in the prediction of performance outcome but not in the prediction of level of achievement.