Alterations in the hemocyte population ofPeriplaneta americana (L.) during starvation and desiccation were studied for 11 days. Total hemocyte count showed increasing trend throughout the starvation period. Changes in differential hemocyte count were evident. Plasmatocytes and granulocytes decreased marginally. Increase in coagulocyte count occurred from 6th day onwards. Two-fold increase in the total hemocyte and differential count was pronounced during subsequent days. During the combined stress period total hemocyte count was significantly higher. Differential hemocyte count was also altered. Degenerative changes set in during late phases of the experiment. The causal factors for such changes in hemocyte population under experimental stress are discussed.