OBJECTIVES: To examine the gene expression alterations in rat’s brain, treated by non-ionizing electromagnetic radiation from 900MHz-GSM mobile phone is main aim of this study.  METHODS: We investigated whether  an exposure of GSM-900 MHz irradiation from the mobile phone (3hours/day up to 28 days) could lead to the modulation of gene expression pattern in the rat brain. All rats were habitualised for one week prior to start the experiment in well designed circular mobile phone exposure (CCPE) cage. CCPE cage was specially designed for EMR exposure by mobile phone on the rats in the natural environment and it placed inside the exposure room where other electric appliances were not installed. In the cage, mobile phone was placed in the center and rats were allowed to move around the device within 10 cm. radius. After 28 days, mRNA from the brain of control, sham and GSM-900 MHz exposed rats were isolated and subjected to quantitative Real Time Polymerase Chain Reaction (qRT-PCR) array analysis. Gene expression was measured and expressed in fold change as described by Bandhyopadhay et.al. (2007). The qRT-PCR was performed by using sybr green chemistry on ABI 7900HT platform. The real time quantification of amplification was done by measuring change in fluorescence by SDS2.3 software and further analyze by RQ manager. RESULTS: Thus the results obtained from this study have shown that there is no significant change in expressions of genes involved in DNA damage and repair pathways such as chromatin assembly (CHAF1A), DNA damage checkpoints (Chk1), DNA synthesis (POLD1), post-transcriptional processes (RBM4), translation synthesis (POLI) and stress signaling (Hsp90) as compared with controls. CONCLUSIONS: Mobile phone’s acute exposure (GSM900MHz) does not support for genes expression involved in DNA damage and repair pathways.