delta-Aminolevulinate (A1A) synthase activity was determined in the Harderian glands of male and female Golden Hamsters. 2. The enzyme activity was higher in the female gland than in the male gland. 3. The data suggest that the higher enzyme activity is, at least partly, related to the higher porphyrin content in the female gland. 4. This enzyme activity has not been reported in the male gland previously.