Six human volunteers were exposed to 10 and 20 ppm carbon disulfide at rest and to 3 and 10 ppm carbon disulfide under a 50 W level of physical exercise during four consecutive periods of 50 min. Every 5 min a sample was taken from the mixed exhaled air in which the concentration of carbon disulfide was determined. It was established that only an apparent steady state was reached during this exposure period. The retention values were established as 0.374 (SD = 0.106; n = 239) for exposure to 10 ppm carbon disulfide at rest and as 0.410 (SD = 0.103; n = 239) for exposure to 20 ppm carbon disulfide at rest. During exposure to 10 ppm and 3 ppm carbon disulfide, combined with a 50 W level of physical exercise, the retention values decreased to 0.286 (SD = 0.083; n = 239) and 0.277 (SD = 0.049; n = 239) respectively. Thereby, the measured individual retention values of carbon disulfide show considerable interindividual differences. The respiratory uptake of carbon disulfide (mg CS2) proved significantly influenced by the amount of body fat estimated from skinfold thickness measurements. The respiratory elimination of carbon disulfide in the exhaled air can be described by means of a two-exponential decay.