Papers and reports from the 1979 Workshop on Recommended Heat Stress Standards are presented. The workshop participants included experts from industry, labor, OSHA, and academia, and was conducted under the auspices of NIOSH. Papers were presented on topics such as heat stress tolerance testing, comparison of heat action stress levels, and design of work rest schedules for hot jobs. Preemployment selection criteria for hot job workers also are discussed along with accident prevention methods. Recommendations are included for an improved heat stress standard and for additional research.