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 samples 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. A more sensitive method for determination of DDA excretion levels in urine is needed, since the present procedure gives values below the limit of sensitivity for about three fourths of subjects from the general population group.