The optimal availability of immune cells in the peripheral blood stream of women plays a critical role in their response to disease and therapeutic interventions. Interaction between the reproductive and immune system plays an important immunoregulatory role. This study was designed to examine the impact of different phases of menstrual cycle on the blood leukocytes. Twenty-four healthy women in their reproductive age group and having regular menstrual cycle were studied during menstrual, proliferative and secretary phases of menstrual cycle. Total leukocyte count, absolute and differential counts of neutrophils, lymphocytes and mixed cells (includes eosinophils, basophils and monocytes) were analyzed. Results showed that the variations in the different types of leukocytes during different phases of menstrual cycle were not statistically significant. No significant inter group difference, except for the significant decrease in differential lymphocyte percentage in proliferative phase as compared to menses were observed.