The main objective was to evaluate antidepressant effect of diltiazem in rats. Results of numerous pre-clinical studies have demonstrated that calcium channel blockers have an antidepressant activity & a potential for interaction with standard antidepressants. The present study is designed to test this hypothesis in rats .Rats were assigned to six groups,  one group is the control group (distilled water) , three groups are ,imipramine (10 mg/kg), venlafaxine (10 mg/kg), and diltiazem (10mg/kg) alone and other two groups are combination of diltiazem with imipramine, and diltiazem with venlafaxine. To know the antidepressant effect, forced swim model had been used, the immobility period of all the groups are compared with each other  after giving drugs for 7 days Diltiazem produced significant antidepressant effect either alone or in combination with imipramine. The efficacy of diltiazem (10mg/kg) was comparable to that of imipramine (10mg/kg) and venlafaxine (10mg/kg) results of the present study indicate antidepressant like activity of diltiazem