A 49-year-old man with a history of left nasal discharge and nasal cavity blockage for 5 months was diagnosed with sino-nasal mucosal malignant melanoma on nasal biopsy. On CT scan, the tumour involved the nasal cavity, left maxillary sinus, ethmoid sinus and medial left orbit. The tumour was grossly excised and adjuvant radiation therapy was offered. The patient was planned for an Intensity Modulated Radiotherapy technique to keep tolerance doses of organs at risk within normal limits and at same time deliver the intended dose of radiation to the tumour site, using 66 Gy in 33 fractions. Owing to the anatomical complexity of the sino-nasal region, precision radiotherapy (RT) is mandatory to optimally irradiate the tumour area while sparing critical surrounding normal structures from late toxicity of RT. Established dose constraints for at-risk organs can only be accomplished through this novel technique of RT. However, despite advances in techniques, current treatment modalities have not significantly made an impact on survival of these patients.