Background The genus Albizia (Leguminoseae) is used in folk medicine for the treatment of a wide range of ailments. Recently, saponins from plant origin have attracted much attention. Saponins are recorded to have a broad range of biological and pharmacological activities. This study was performed to evaluate the protective role of Albizia chinensis bark methanolic extract (MEAC) against the genotoxicity induced by cyclophosphamide (CP) using different mutagenic parameters. Results The results showed that MEAC induced an inhibitory effect against chromosomal aberrations of CP in mouse bone marrow and spermatocytes. Such effect was found to be significant (p < 0.01) with a dose of 100 mg/kg treated once for 24 h and also after repeated treatment at a dose of 25 mg/kg for 7 days. In sperm abnormalities, the protective effect of Albizia extract showed a dose-related relationship. Different doses of MEAC (25, 50, and 100 mg/kg) significantly (p < 0.01) ameliorated sperm abnormalities induced by CP dose-dependently. The percentage of sperm abnormalities was decreased to 5.14 ± 0.72 in the group of animals treated with CP plus MEAC (100 mg/kg) indicating an inhibitory effect of about 50%. Conclusion MEAC at the doses examined was non-genotoxic compared to control (negative) and exhibited a protective role against CP genotoxicity.