23 patients affected by phakomatoses were studied with NMR, including tuberous sclerosis (11 cases), Sturge-Weber's disease and Von Recklinghausen's neurofibromatosis (6 cases). SE sequence was used performing T1-WIs with TR = 350-750 ms and TE = 20-30 ms and T2-WIs with TR = 1500-2100 ms and TE = 50-100 ms. Tuberous sclerosis was characterized in each case by the presence of hiperintense areas in T2-WIOs, associated in 9 cases to subependimal microcalcifications. Sturge-Weber-disease showed: cerebral or lobar emiatrophia, abnormal vascularization and cortical calcifications. Cerebral neurofibromatosis was characterized by extra-assial tumors, associated in 4 cases to gliomas of the optical pathways. The AA. conclude that NMR is the choice examination in the evaluation of phakomatoses.