Cyclophosphamide (CP) is commonly used in regimen of treatment of cancers and autoimmune diseases as systemic lupus. Hepatotoxicity and bone marrow depression are acute side effects of CP through inducing oxidative stress. The concomitant use of captopril ameliorates these side effects. This study aimed to evaluate the possible protective effects of captopril against hepatotoxicity and bone marrow depression induced by CP in adult albino rats. In this experimental study, 60 rats were divided into 4 groups;, the captopril treated group (capoten tablet 50 mg/kg for 5 days orally), CP treated group (150 mg/kg, a single dose intraperitoneal administration) and the captopril-CP treated group received captopril (50mg/kg for 5 days orally) followed by CP (150 mg/kg, a single dose intraperitoneally). The liver tissues and bone marrow of rats in all groups were subjected to light and electron microscopic studies. The serum levels of liver function markers such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were assessed in blood samples of each group as indicators of liver damage. The results showed that the injection of CP elevated serum ALT and AST compared to the control group. Concomitant treatment of captopril and CP decreases serum levels of ALT and AST. CP treated group showed diffuse lesion of liver tissue and bone marrow. The captopril-CP treated group showed minimal hepatic congestion and decreased adipose tissue in bone marrow. The current study provided that captopril has protective effect against cyclophosphamide induced hepatotoxicity and myelotoxicity.