Background: The aim of this study was to investigate the effects of exposure to a 900-MHz electromagnetic field (EMF) produced by mobile phones on the renal development of prenatal rats. Histopathological changes and apoptosis in the kidneys, together with levels of urea, creatinine and electrolyte in serum were determined. Methods: A total of 14 Sprague-Dawley rats were studied. Pregnant rats were divided into two equal groups: a control group and an EMF-exposed group. The study group was exposed to 900-MHz of EMF during the first 20 days of pregnancy, while the control group was unexposed to EMF. Sections obtained from paraffin blocks were stained for caspase-3 by immunohistochemistry, hematoxylin-eosin and Masson's trichrome. Results: Mild congestion and tubular defects, and dilatation of Bowman's capsule were observed in the kidney tissues of rats in the exposed group. Apoptosis was evaluated using anti-caspase-3; stronger positive staining was observed in the renal tubular cells in the study group than those of the control group. Although there was a significant difference between the study and control groups in terms of K+ level (p < 0.05), no significant difference was observed in the other parameters studied (p > 0.05). Conclusion: Our study shows that the electromagnetic waves propagated from mobile phones have harmful effects on the renal development of prenatal rats.