Ciprofloxacin is one of 2nd generation flouroquinolonesextensively used as antimicrobial agent of many veterinarydiseases caused by gram + ive and gram -ive microorganisms aswell as mycoplasma. Whereas, doxorubicin is largely used asantineoplastic agent in treatment of various tumors .The present study was carried out to study the effect ofciprofloxacin and doxorubicin on some reproductive andbiochemical parameters in mature male rats.Sixty mature albino male rats were used in this study.They were randomly divided into 3 groups as follows:Group (I): Kept as a control group for groups (2 & 3). Itcontains 20 rats and divided into 2 subgroups, the firstone injected i/p with 0.4 ml saline solution once daily for7 days and used as a control group for group 2, and thesecond subgroup was injected with 0.4 ml saline solutiononce weekly for 3 weeks and used as a control for group3Group (11): Comprises 20 rats and injected i/p once daily for 7days with therapeutic dose of ciprofloxacin (9 mg/kgb.wt.).