Apoptosis was first described in 1972 as a novel physiological process by Kerr. Apoptosis can be defined as a distinct morphological form of programmed cell death, which is analogue to "cell suicide" because cells death had never been in doubt. In this study 62 normal individual were involved. 7 ml of blood were aspirated from antecubital vein under strict sterilization, the blood then was processed for lymphocytes separation. The separated lymphocytes were cultured in RPMI media containing L-glutamine and antibiotics, the culture were divided as: - Baseline. - With prooxidants H2O2 10'8 M. -With antioxidants ZnCl2 4.77 x 10'5 M or CuSO4 15 x 10~6 M. -With varying degree of temperature 37 °C, 24 °C, 4 °C. In this study the diagnosis of apoptosis was based on -Morphological features which include; surface morphological features as membrane bleb formation, ichinoid spikes with flattening of lymphocyte, formation of blister and finally apoptotic bodies. -Nuclear changes; including both morphological changes of the nucleus, and DNA quantitation after Feulgen cytochemical reaction. -Biochemical changes: these are indirect measures for the generation of reactive oxygen species, which can be regarded as a method of diagnosis of apoptotic process. These include malondialdehyde, thiol protein, and selenium. Our results showed that in baseline culture about 35% of lymphocyte died after 24 hours of in vitro culture, then after 72 hours all lymphocytes were found to be apoptotic. These are assessed morphologically and biochemically where the MDA level was increased gradually with progress of apoptotic process while thiol and selenium were consumed with progress of apoptotic process. In the second group incubation with prooxidant H2CO2 , facilitates the process of apoptosis as 11% of cells died within 10 minutes, and 100% died after 24 hours of in vitro culture. While lymphocyte cultured with antioxidants zinc and copper showed a slow rate of cell death. In the first 24 hours 25% f lymphocytes were apoptotic and after 72 hours about 60% of lymphocytes were apoptotic. Measurement of biochemical parameters showed increase in MDA and decrease in thiol and selenium. In the third group i.e. lymphocyte cultured at low temperature', showed reduced apoptotic process. After 24 hours of in vitro culture at low temperature (4 °C, 24 °C) only 4% of lymphocytes were apoptotic, while after 72 hours incubation at 4 °C, 32% of lymphocytes were apoptotic, and at 24 °C 50% of lymphocytes were apoptotic. From this study we can conclude that lymphocyte apoptosis is a physiological form of cell death due to the generation of free radicals, this apoptotic process can be stimulated by prooxidants such as H2O2 or inhibited by antioxidants. The apoptotic process can be suppressed markedly by reducing the temperature.