Objectives : This study aimed to assess the expression of heme oxygenase-1 in seminal plasma as well as testicular tissue to elucidate its relation with spermatogenic process and male infertilety. HO-1 was not detected in sperms and seminal plasma. HO-1 expression in testicular tissue especialy in azospermic cases revealed its relation to spermatogenic process as well as histopathological differentiation.