The present study was undertaken to assess the testicular toxicity following short-term exposure to cypermethrin (α-CP) in albino mice. Cypermethrin was dissolved in arachis oil and administered to two groups of mice (n = 12/group) orally at the dose rate of 250 mg/kg body weight, once a day for 28 days. Fifty percent of the animals in both the groups were sacrificed on day 14 and the remaining on day 28. Plasma samples were subjected to radioimmunoassay to determine testosterone levels. The testes were collected to determine the cholesterol levels and the activity of transaminases (AST and ALT) or epididymal alkaline phosphatase (ALP). Histological study of testicular tissue was also undertaken to examine the α-CP-induced ultrastructural changes using transmission electron microscopy (TEM). α-CP significantly (P<0.05) increased the activities of testicular AST (1.36±0.12 vs. 1.19±0.10), ALT(1.78±0.11 vs. 1.36±0.09), and significantly (P<0.05) decreased the testosterone levels (0.86±0.24 vs. 1.72±0.18). Testicular cholesterol levels were elevated in treated animals as compared to control (1.81±0.16 vs. 1.42±0.08). Epididymal alkaline phosphatase (ALP) activity was also decreased significantly (P<0.05) in treated animals (1.10±0.20 vs. 1.64±0.1). Histological studies on day 28 revealed rupture of spermatogonic cell membrane, shrinkage in the nucleus, stages of apoptosis, condensation of chromatin, and decreased cytoplasmic organelles. The study suggested that short-term exposure to α-CP in albino mice induced toxicopathological lesions in testicular tissue leading to decreased plasma testosterone levels.