Objectives: The main aims of study were to compare toxicity profile of IMRT with conventional Radiotherapy (2D RT) in head and neck cancer. Methods: The Study was a prospective one in which we included Eligible patients known case of head and neck cancer like oral cavity, nasopharaynx, oropharaynx, and hypopharyanx to received either definitive chemoradiation alone or adjuvant. Eligible patients in conventional group randomized to receive radiotherapy with parallel opposed lateral fields and one direct anterior lower neck. In IMRT group patients received either 7 fields or 5 fields or parotid sparing radiation. Patients Toxicity pattern (grades of mucositis, skin reaction, xerostomia, odynophagia) of both groups was noted down. Toxicity of Radio-Therapy (RT) developing within 90 days and more than 90 days from the beginning of RT assessed according to Radiation Therapy Oncology Group (RTOG) and European Organization for the Research and Treatment of Cancer (EORTC) criteria. Results: A total of 30 patients were available for the analysis, 15 patients were in conventional group and 15 were in IMRT group. Patients who developed toxicity was compared both groups. Acute toxicity as well as late toxicity is concern in present study, it has been found that in conventional group toxicity is more common other than skin toxicity as compared to IMRT group. Conclusion: Although for some side-effects, the benefit of IMRT on conventional RT cannot be easily proven, the majority and present study show a reduction in toxicity when using IMRT in head and neck cancer. IMRT should be used in all head and neck cancer patients, in order to try to reduce the devastating side effects. Continuous prospective data collection on toxicity and outcome will provide us more data in the future, supporting this technological progress.