The widespread use of electromagnetic devices such as mobile phones (GSM) raises the fear about possible health hazards from exposure to radiofrequency (RF) radiation, especially during the stage of pregnancy. Since the early life (embryo, fetus) is at a higher risk of environmental toxicants and it is considered more vulnerable than adults because their immune system is still developing. The goal of our study was to evaluate whether whole-body exposure in utero to non-thermal radiofrequency (RF) radiation from cellular phones could induce cytogenetic effects on peripheral blood lymphocytes of immature rats. Twenty Wistar immature rats were exposed only in utero to 900 MHz at SAR of 0.873-0.352 W/kg, for 0h (control), 1h, 2h and 3h daily, 7 days a week. All rats were visually checked daily, body weight and length were measured weekly starting the 2 weeks after their birth. Nine weeks after the delivery, blood samples were collected from all groups and peripheral blood cultures were performed using standard laboratory methods for the extent of genotoxicity, assessed by the cytokinesis-block micronucleus assay. No differences in micronucleated (MN) cells and proliferation index in immature rat lymphocyte cells were found among the study groups. The body weight and length gains were also insignificantly changed in all groups exposed comparing to unexposed rats. This study shows that the exposure only in utero to 900 MHz radiofrequency radiation from cell phones following by 9-week recovery period may not induce cytogenetic alterations in immature rat lymphocytes.