OBJECTIVE: Porphyries are metabolic disorders of the haem biosynthetic pathway. They result from excessive accumulation of neurotoxic porphyrin precursors. Unlike the majority of Inherited Metabolic Diseases, the porphyries manifest after puberty, and their occurrence in childhood is very rare. PATIENT AND METHOD: The authors report a case of acute intermittent porphyria in an 8-year-old girl, reviewing the literature on etiopathogeny, diagnosis and treatment. COMMENTS: The authors emphasize to the importance of diagnosis in these patients, since the clinical expression may be lifethreatening and requires exposures to precipitating factors, so it may be prevented.