Cytotoxic chemotherapy for malignant disease has markedly improved the chances of long-term remission or cure in young patients who have not yet started a family. Germ cells are important targets of many chemicals. Germ cell mutagens irrespective of their chemical nature and properties, affect population of cells in the gonads, especially of testis. There is paucity of reports on planned study of imatinib on testicular function. Hence a study was planned to assess the effects of imatinib on testicular functions in male swiss albino mice. Male swiss albino mice were treated with imatinib and sacrificed at the end of 1, 2, 4, 5, 7 and 10 week after the last exposure to imatinib. The testis were removed, weighed and processed for histological analysis. Qualitative analysis of the testis showed sloughing of the germ cells, reduction in the number of sperm cells and variation in the size and shape of the seminiferous tubules. There was not much change in the diameter of the seminiferous tubules in the treated groups except for the higher dose group. The epithelial height was reduced significantly in all treated groups. Imatinib does affect the histopathology of mice testis significantly, but this effect is reversible once the drug is withdrawn. Imatinib had demonstrated high levels of efficacy in gastrointestinal tumors and also chronic myeloid leukemia. This finding may help the clinicians to plan and address the fertility related issues in young patients of reproductive age who are being treated with imatinib for gastrointestinal tumors and chronic myeloid leukemia.