The Mauriac syndrome is a rare complication of poorly controlled diabetes mellitus in adolescence. It is characterized by hepatomegaly, growth and puberty delay, and the presence of elevated transaminases and serum lipids. We report the case of a 17-years-old patient with type 1 diabetes who got admitted for evaluation of growth retardation. The clinical examination showed failure to thrive, hepatomegaly and abdominal distension. Blood sugar was very high. Blood transaminases were also high. Abdominal ultrasound showed homogeneous hepatomegaly. Viral hepatitis serologies and autoimmune study were negative. Liver histology analysis after liver biopsy comfirmed the hepatic glycogenosis. After glycaemic control was improved, liver enzymes normalized and the adbominal distension regressed.