We report three cases of hereditary hemorrhagic telangiectasia in one family. The punctiform, spider-like and nodular telangieectatic lesions were presented in these all patients, the father, son an daughter. But nevus flammeus-like lesion which was the unusual manifestation of hereditary hemorrhagic telangiectasia was noticed on daughters chest. There were no abnormal laboratory findings and no evidence of systemic disease. Histological findings showed only dilated telangiectatic blood vessels in the upper dermis. (Kor J Dermatol 28(6): 826 830, 1990)