Genetic and epigenetic changes are involved in initiation and progression of cancer. We exposed peripheral blood cells from young male volunteers to CW 800MHz radiation at SAR values of 2.9 and 4.1 W/kg for 24 hours (n=5) and 72 hours (n=10). Control experiments were carried out in the temperature range of 33.5-40°C. Epigenetic changes were monitored by analysis of FISH patterns of centromeres of chromosomes 11 and 17 reflecting alteration in their replication timing and synchrony. Our results demonstrate radiation induced non-thermal effect on the level of asynchronous replication in both chromosomes following exposure to the higher SAR level.