Background: Lysinuric protein intolerance (LPI) is an autosomal resessive aminoaciduria affecting the transport of cationic amino acids (CAA; arginine, lysine, ornithine) at the basolateral membrane of epithelial cells in the intestine and kidney. LPI manifests with vomiting, attacks of coma, mental retardation due to hyperammonia episodes, diarrhea, failure to thrive, hepatosplenomegaly, bone marrow abnormalities, osteoporosis, pulmonary alveolar proteinosis, altered immune response and chronic renal disease. Case Report: 36 year old female patient followed with vomiting, failure to thrive during childhood consulted for glycogen storage disease type 7 with signs of mild haemolysis and glycogen storage at liver biopsy. Lysinuric protein intolerance was suspected with findings of vomiting attacks and failure to thrive during childhood, protein aversion, short stature, osteoporosis, hyperferritinemia, hemophagocytosis, mild hemolysis,glycogen storage at liver biopsy, elevated lactate dehydrogenase, hypercholesterolemia and hypertrigliceridemia. The patient was diagnosed as LPI by low plasma levels and high excretion to urine of CAA.