Heat dissipation is influenced by environmental conditions, workload, and clothing worn on the job. To account for the effects of clothing, clothing adjustment factors based on WBGT have been proposed. Beacuse heat dissipation mechanisms may differ between males and females, gender-specific clothing adjustment factors may be appropriate. PURPOSE: To determine the gender effects on clothing adjustment factors based on critical WBGT. METHODS: Thirteen healthy adults (M = 8, F = 5) performed a total of 15 work bouts in each of three environmental conditions (hot, dry; warm, humid; and 50% relative humidity) wearing each of 5 ensembles (cotton work clothes, cotton coveralls, particle barrier-Tyvek 1424, water-barrier, vapor-permeable-NexGen LS417, and vapor-barrier-TyvekQC). Core temperature, heart rate, average skin temperature, and ambient conditions were recorded every 5 minutes. Testing sessions lasted approximately 120 minutes unless one of the termination criteria was met. Critical WBGT for each condition was recorded as the WBGT five minutes prior to the loss of thermal equilibrium as evidenced by a progressive rise in core temperature. RESULTS: A three-way analysis of variance found no gender effect on critical WBGT for any ensemble (p > .05). However for the total sample, there was a significant difference in critical WBGT between ensembles (p < .05). The critical WBGTs for cotton coveralls, cotton work clothes, and Tyvek 1424 (WBGT = 34.20, 34.12, and 33.56, respectively) were significantly greater than NexGen LS417 (WBGT = 31.95). The lowest critical WBGT was found for Tyvek QC (WBGT = 26.33). CONCLUSIONS: These results suggest that there is no difference in critical WBGT for the ensembles tested between males and females. The cloting adjustment factor for Tyvek QC is approximately 8* and the clothing adjustment factor for NexGen LS417 is approximately 2*. Supported by the National Institutes of Occupational Safety and Health