Introduction: Menstrual cycle is the periodic shedding of endometrium accompanied by loss of blood during reproductive age.The period extending from the begining of menses to the begining of next one. The regulation of the normal cycle is under the control of neuro hormonal mechanisms with its feedback system present in the hypothalamic-pituitary-ovarian axis. This study was taken up to see the alterations in the immune cells(leukocytes cells) during menstrual cycle in the Medical students of Jawaharlal Institute of Medical sciences.