Cyclophosphamide (CP) is extensively used as an antineoplastic agent for treatment of various cancers, as well as an immunosuppressive agent. However, despite its wide spectrum of clinical uses, CP is known to cause several adverse effects including reproductive toxicity in humans and experimental animals. Crataegus monogyna is one of the oldest medicinal plant has been shown to be cytoprotective by scavenging free radicals. The present study was conducted to assess whether Crataegus monogyna fruits aqueous extract with anti-oxidant properties could serve as a protective agent against reproductive toxicity during CP treatment in a rat model. Male Wistar rats were categorized into four groups. Two groups of rats were administered CP at a dose of 5 mg in 5 mL saline kg-1 per day for 28 days by oral gavages. One of the groups received Crataegus monogyna aqueous extract at a dose of 20 mg kg-1 per day orally four hours after cyclophosphamide administration. A vehicle-treated control group and a Crataegus monogyna control group were also included. The CP-treated group showed significant decreases in the body and organ weights and spermatogenic activities as well as many histological alterations. CP treatment also caused a significant decrease in sperm count and motility with an increase in dead and abnormal sperms. Moreover, significant decrease in serum levels of testosterone and increased serum concentrations of FSH, LH, LDH, CPK and SGOT were observed in CP-treated rats. Notably, Crataegus coadministration caused a partial recovery in above-mentioned parameters. These findings indicated that Crataegus might be partially protective against CP-induced reproductive toxicity.