In rats intraperitoneal injection of lead (8 mg/kg as Pb-acetate) over a period of 15 days induced histoenzymic and histological alterations in the testes. Histopathological examination revealed at places degeneration of seminiferous tubules. There were patchy areas showing marked loss in the activity of succinic dehydrogenase and adenosine triphosphatase whereas alkaline phosphatase activity showed only slight inhibition in treated rats. These alterations suggest that in the initial stage of exposure to lead, the disruption of cellular energetics and cation transport in the testicular tissue may be responsible for altering the germinal function of the testis.