Recent research (Choma et al., 1998) has demonstrated transient mood changes and impairment of short-term memory in collegiate wrestlers as a result of rapid weight loss (RWL) of at least 5% body weight prior to competition.  The purpose of this study was to examine the effects of RWL on cognition and affect in high school wrestlers.  Wrestlers were considered to be engaging in RWL if they were losing greater than 5% body weight (n = 14).  Wrestlers losing less than 1% of body weight (n = 14) were considered maintainers and served as the control group.  Both groups of wrestlers were given a battery of tests assessing cognitive performance (Trail Making Tests A and B, Stroop Color-Word Test, Digit Span, and Choice RT) and mood state (PANAS) at normal weight (5-10 days prior to competition) and again 8-12 hours prior to weigh-in.  Results indicated an average weight loss of 4.68 kg in the RWL group and an average loss of 0.29 kg in the control group.  A group by time MANOVA and univariate follow-up tests indicated that there was a significant group by time interaction for positive affect (p < 0.05), with the RWL wrestlers exhibiting less positive affect in comparison to the control group just prior to weigh-in.  Similar differences were demonstrated for negative affect (RWL exhibiting increased negative affect), which approached significance (p = 0.06).  However, none of the cognitive performance tests demonstrated significant differential changes for RWL vs.control groups (p > 0.10).  With competition effects and re-feeding issues controlled in the present study, results suggest that there are mood disturbances, but not cognitive impairments, associated with RWL of at least 5% body weight in high school wrestlers.