We report a Mexican family with 15 members affected with hereditary hemorrhagic telangiectasia (HHT), all of them suffering from severe hemorrhagic episodes treated with multiple blood transfusions; one patient had a cerebral arteriovenous fistula that required surgical treatment and two others had severe cirrhosis of the liver. Clinical findings in this family illustrate the variable expressivity in HHT, which should be taken into account for the purpose of genetic counselling and monitoring for early detection of systemic complications.