Daily sperm production in rats and monkeys were estimated by extended histometric method. Individual seminiferous tubules were separated, fixed, processed and embedded. Semi-thin sections were stained with toluidine blue and the different cell types quantitated with Chalkley’s eye piece. The daily sperm production estimated was compared with that obtained by the homogenization method. The results indicate that daily sperm production obtained by both the methods were comparable. The present histometric method has an added advantage of requiring very small amount of biopsy material to give precise daily sperm production estimations.