Exposure to glucocorticoids (GCs) leads to numerous changes in various biological systems including the reproductive system. The aim of the present study was to find out whether dexamethasone (Dex), a widely used GC, would influence the apoptosis and expression of Bax, an important proapoptotic protein, in the mouse testicular germ cells. Experimental groups of 8 male NMRI mice received one of the following treatments daily for 7 days: 4, 7 and 10 mg/kg Dex. Control groups were treated with equivalent volumes of saline. Experimental and control animals were sacrificed 24 h after the last injection. Immunohistochemical procedure was used to evaluation of Bax expression and the deoxyuridine nick-end labeling (TUNEL) was applied to assessment of the apoptotic germ cells. Bax expression was upregulated mainly at stages VII-VIII of spermatogenic cycle (p<0.05) in experimental groups. Apoptotic index was significantly increased in 7 and 10 mg/kg Dex treated mice (p<0.05). It appears that GCs such as Dex could induce apoptosis through the expression of proapoptotic proteins.