Introduction: Tyrosinemia type I (HT1) is a rare congenital metabolic disorder of tyrosine metabolism, resulting in the accumulation of toxic metabolites that damage the liver and kidneys. Case Report: A 16 month old girl presented failure to thrive, rickets, significant visceromegaly (hepatomegaly with hepatic nodules, splenomegaly and nephromegaly) and anaemia. Her psycho-motor development was delayed. The height, weight were less than 2nd percentile. Fanconi syndrome was suspected. TMS showed highly elevated levels of tyrosine (568 mcmol/L, normal< 200), and phenylalanine (205 mcmol/L, normal<125). Other biochemical investigations showed high concentration of urine succinylacetone (542 mmol/mol de creat, normal<20) and alphaphetoprotein 1750 ng/ml normal<13.4). The hepatic transaminases, alkaline phosphates were elevated too. Genotype is IVS12+5 g/aSer352Arg. She has been treated since the age of 18 months with Orfadin (dose 1 mg/ kg/day) and with the phenylalanine-and tyrosine-restricted diet with good response and tolerance and adequate metabolic status is maintained. Her mental and motor developments have normalized.