Aim: To compare toxicities and outcome in head and neck cancers patients treated with IMRT and 2D conformal radiotherapy along with concurrent chemotherapy. Materials and Methods: Patients presenting to the Department of Radiation oncology with head and neck squamous cell cancers TNM staging T14 N03 M0. Twenty patients of head and neck cancer and 20 undergoing conventional 2DConformal Radiotherapy alone served as controls were included in this study. Results: Most of these patients were found to be in highly advanced stage of disease with poor nutritional status and poor performance status (stage III and IVA) at the time of diagnosis. All the 40 patients received concurrent cisplatin chemotherapy. All the patients were examined and graded for mucositis, dysphagia, xerostomia, skin reactions and tumor response. This study was conducted to compare whether Simultaneous Integrated BoostIntensity Modulated Radiotherapy (SIBIMRT) could reduce radiotherapy induced acute mucositis, dysphagia, xerostomia and increase tumor response and tolerance to it in head and neck cancer patients compared to standard conventional Radiotherapy. IMRT may have had a role in reducing the incidence, delaying the onset & diminishing the severity of mucositis in some patients. However it did not completely prevent the occurrence of mucositis. Our study demonstrated that the IMRT may not reduce the incidence of dysphagia. It may be because of high dose per fraction in IMRT delivered to swallowing apparatus. IMRT reduced the incidence of xerostomia. Also the duration of xerostomia was decreased by IMRT. IMRT was also able to reduce the dose to parotids along with adequate coverage of planning target volume. Submandibular glands received less doses, particularly in hypopharyngeal and nasopharyngeal cancers. The contralateral parotid in all IMRT patients were within the tolerance dose of 26 Gy of mean dose. In few selected IMRT patients depending on the primary site, ipsilateral parotid were confined to their tolerance doses of 26 Gy of mean doses. Our study did not show any benefit for tumor response due to IMRT. However the incidence of recurrence is reduced due to IMRT. Conclusion: IMRT offers a safe, effective, reduction of normal tissue dose in head and neck cancer patients undergoing radiotherapy & was generally well tolerated. Hence we recommend using IMRT in head and neck cancer patients undergoing radiotherapy in order to reduce RT induced acute mucositis and xerostomia.