INTRODUCTION: Glucose-6-phosphate dehydrogenase deficiency (G6PD deficiency) is 
the most common red blood cell (RBC) enzyme disorder. The decrease as well as 
the absence of the enzyme increase RBC vulnerability to oxidative stress caused 
by exposure to certain medications or intake of fava beans. Among the most 
common clinical manifestations of this condition, acute hemolysis, chronic 
hemolysis, neonatal hyperbilirubinemia, and an asymptomatic form are observed.
OBJECTIVE: To analyze the case of a child who presented hemolytic crisis due to 
favism.
CASE REPORT: A 2 year and 7 month old boy with a history of hyperbilirubinemia 
during the newborn period with no apparent cause, no family history of hemolytic 
anemia or parental consanguinity. He presented a prolonged neonatal jaundice and 
severe anemia requiring RBC transfusion. An intake of fava beans 48 h prior to 
onset of symptoms was reported. G6PD qualitative determination was compatible 
with this enzyme deficiency.
CONCLUSION: G6PD deficiency can be highly variable in its clinical presentation, 
so it is necessary to keep it in mind during the diagnosis of hemolytic anemia 
at any age.