Benign fibro-osseous lesions are diverse group characterized by the replacement of normal bone by tissue composed of collagen fibers and fibroblasts that contain varying amounts of mineralized substance, which may be bony or cementum-like in appearance. Ossifying fibroma, one of these benign fibro-osseous lesions, is usually found in the mandible of young or adult women. Authors experienced four cases of sinonasal ossifying fibromas involving nasal cavity, paranasal sinuses, orbit, and anterior skull base, which were successfully managed by enucleation with or without using craniofacial approach. Also we found that the delineation of the tumor is much easier on MR than CT by the enhancement of the solid part of the tumor including the thick outer shell.