Cancers of the paranasal sinuses are rare tumors, with treatment based on a multidisciplinary approach. Surgery and radiation therapy, possibly associated with chemotherapy are used to obtain 5 years specific survival rate of 60-70 %. Advances in radiotherapy, including the use of imaging for 3D conformal approach require precise knowledge of the radioanatomy for this type of tumor to determine the different volumes of interest. Purpose of this study was to specify radioanatomy and conformal radiation modalities for cancers of the sinuses, and is illustrated by a case report.