Objectives: The study is a comparative randomized study between two groups of patients, the aim of which is to compare 3D conformal radiation therapy (3D-CRT) and intensity modulated radiation therapy (IMRT) as newer modalities in treating nasopharyngeal carcinomas; evaluating and comparing both techniques as regard their efficacy on tumor response, local control and treatment related toxicity as well as a dosimetric comparison between both techniques.Patients and Methods: Between February 2010 and December 2011, 20 patients with nasopharyngeal carcinoma were treated by 3D CRT technique (Group A) and compared to another 20 patients treated by IMRT (Group B). Both groups were treated at Kasr El-Ainy Center of Clinical Oncology and Nuclear Medicine (NEMROCK).The two groups were treated concurrently with platinol based chemotherapy as a weekly sensitizer and post-radiotherapy with cisplatin and 5-FU for 3 cycles. Patients were assessed for treatment related toxicity using the European Organization for research and treatment of cancer, the Radiation Oncology Group (EORTC/RTOG) and the National cancer institute common toxicity (NCI). Results: Group A showed a higher incidence of treatment related toxicity than in group B particularly xerostomia. IMRT was clearly able to preserve the parotid gland function. Between February 2010 and December 2011 with a median follow up 20 months for both groups, all patients entered in complete remission after treatment except one in group A. Local control rates were 95% and 100% for groups A and B respectively. Results of the dosimetric comparison between both techniques showed that IMRT had a better tumor coverage and conformity index. As for the dose homogeneity it was also better in the IMRT plans and the reason for this was attributed to the dose inhomogeneity at the photon/electron junction in the 3D-CRT plans. Also, doses received by the risk structures, particularly parotids, was significantly less in the IMRT plans than those of 3D-CRT. A statistically significant difference was also observed in the V30 to the parotid gland, which was 95.8% and 39.3% with CRT and IMRT, respectively (p < 0.001). IMRT reduced mean doses to the cochleae from 53.3 Gy to 46.8 Gy (right side) and 49.16 Gy to 42.72 Gy (left side) with a p-value of 0.008 and 0.013, respectively. Maximum doses to the spinal cord, brainstem, chiasma and temporal lobe were greater for patients treated by CRT compared with IMRT (p < 0.05, for all).Conclusion: IMRT technique was clearly able to increase the dose delivery to the target volume, improve conformity and homogeneity index and spare the parotid glands and reduce dose to the risk organs in comparison to 3D-CRT.