The excretion of DDA in urine by people in various dietary, environmental, and occupational exposure groups with regard to DDT contact was determined. The DDA excretion levels for the general population ranged from below the experimental limit of the analytical method (0.02 ppm) to 0.35 ppm. Of the 79 sampels in this group which were tested, 56 (74%) did not contain detectable quantities of DDA. There was no indication that any important difference in DDA excretion level existed among the general population, meat abstainers, or people with heavy environmental or light occupational exposure. However, striking differences in DDA excretion exist for groups with widely different degrees of exposure.