The in vivo levels of zinc, copper, manganese and iron were determined in the testis, kidney and three brain regions (cerebellum, cerebrum and medulla oblongata) from rats intraperitoneally injected with 20 micrograms per kg body weight of aflatoxin B1 for 6 weeks. Similar investigations were made after a recovery period of 6 weeks. The results obtained were compared with those of pair-fed control rats. The aflatoxin B1-induced decrease in testicular zinc was not reversed after the recovery of the rats. On the contrary, the significantly increased zinc concentration in the other organs following aflatoxin B1 exposure, reverted to the control level, as judged by significant levels. Only in the kidney was there accumulation of copper, even after the cessation of aflatoxin B1 administration. The marked increase in the manganese concentration of all the organs following repeated toxin administration, persisted only in the brain regions after the recovery. Aflatoxin B1 treatment significantly decreased the iron concentration in the testis, kidney, cerebellum and cerebrum. Recovery did not alter this trend. Iron concentration in the medulla oblongata was, however, not significantly changed in the presence of aflatoxin B1. The present data suggest that the repeated administration of aflatoxin B1 to rats could result in either a permanent or temporary re-distribution of these elements in the organs examined.