Cadmium (Cd) is a heavy metal and a major environmental pollutant. The general population is exposed to Cd mainly via drinking water and food products. We have developed a mouse experimental model to investigate the in vivo effects of Cd and the chelating agent monensin on testis and sperm count during adulthood. Animals were divided into three groups: normal control (receiving distilled water and food): Cd group, exposed to 20 mg kg-1 b.w. Cd(II) acetate for the first 2 weeks of the experimental period and Cd+monensin group, receiving monensin (18 mg kg-1 ) after Cd-intoxication (from 15 th to 28th day). Histological observations of the testis demonstrated that Cd induced desquamation of germ cell and their assembly in the luminal region of the tubules. Areas in the testis without spermatides in latest steps of differentiation were also observed in this group. Monensin administration to Cd-treated animals restored histology of the testis to normal to a great extent (despite some Sertoli-cell-only tubules). Statistically significant changes in sperm count were not established for any of the experimental groups. Monensin can reduce injury of the testis and normalize its morphology after subacute exposure to Cd. The results of the present study demonstrated that monensin is a good compound in chelating therapy of some heavy metal intoxications.