Clinical studies on twenty-three patients with multiple neurofibromatosis seen during the past five years at the Department of Dermatology, Busan National University Hospital, were made; the bizarre and varied clinical manifestations of the disease and significances of some kind of skin signs were emphasized. The results obtained were as follows; 1) There were 10 males and 13 females in this series. The age at the first visit varied from 6 to 42 years. 2) family history was noted in 4 cases(17.4%). 3) Approximately half of the patients were transferred from other departments during the course of medical consultation for complaints other than skin disorders. 4) Cutaneous neurofibromata were found in 20 of 23 cases(86.9%) and 4 cases including one case with no cafe-au-lait sports and 3 with no skin tumours were considered as "formes frustes" of the disease. 5) Cafe-au-lait sports, measuring greater than 1.5cm in its longest diameter, were found in 22 cases of 23 and numbered varying from only one to 26. Among 22 patients with the spots, 21 had more than 6 spots of this size. 6) Axillary freckling(Crowe`s sign) was found in 5 cases(21.7%). 7) Malignant changes occurred in one case(4.3%); this patient developed sarcomatous degeneration of neurofibroma at her left shoulder about one year after amputation of the forearn of same side because of benign pachydermatocele. 8) Other skin lesions such as pigmented nevi, nevus anemicus, hairy nevi, sacral hypertrichosis, diffuse bronzing and periorbital pigmentation etc., also were noted. Oral lesions were presented in 3 patients(13.0%), as papular neurofibroma, pouched buccal mucosa and macroslossia with macrocheilia. 9) Skeletal abnormalities were foun din 8 cases(34.8%);kypho-scolosis and skull and facial bone deformities were the most frequent and serious skeletal defects. 10) All the specimens taking from cutaneous neurofibromas represented histologically similar nerve tissue by methyene-blue stain;together with usual features of neurofibroma, marked vascularity, mucoid degenetation and/or cystic formation were also noted in several cases and multiple neurilemmomas in onecase.