We report a new case of thiamine responsive anemia in a three years old boy with the characteristic association of anemia, diabetes mellitus and deafness. Thiamine therapy corrected anemia as described. A thiamine pyrophosphokinase deficiency (TPK) was found which was not influenced by treatment. However normal levels of thiamine pyrophosphate (TPP) were obtained without correction of all symptoms particularly dyserythropoïesis. Thus, etiology of the syndrome is not only a thiamine pyrophosphokinase deficiency as previously suggested.