Intracellular parasites manipulate host cell apoptosis in different ways either to increase their life span within infected cells or to spread infection. The present data provided information on the cellular changes taking place in spleen and peripheral blood during Plasmodium berghei-infection and indicated apoptosis mediated host immune response during infection. Our results suggested a significant change in cellular composition and absolute number of white blood cells in spleen and peripheral blood of P. berghei-infected Balb/c mice. Plasmodium berghei-infection was associated with marked increase in percentage of apoptotic mononuclear cells compared to polymorphonuclear white blood cells.