A male infant with primary combined immunodeficiency, microcephaly with marked cerebellar hypoplasia, and growth failure of prenatal onset is presented. He developed progressive pancytopenia in the 3rd year of life and died at 42 months from disseminated aspergillosis. Laboratory studies and post mortem examination failed to reveal any known aetiology for his disorder. Hreidarsson et al.  previously described a syndrome of progressive pancytopenia with microcephaly, cerebellar hypoplasia and growth failure in three boys, with similar clinical and laboratory findings. Although extensive immunological investigations were not performed in those previous patients, recurrent infections in two of them are suggestive of immunodeficiency. In the light of the immunological findings in our patient, we propose that the condition of the four patients belongs to the same syndrome, which has to be considered as a primary combined immunodeficiency syndrome. This syndrome can be distinguished from the other known immunodeficiency syndromes by its associated characteristic features, namely microcephaly with cerebellar hypoplasia, growth failure of prenatal onset and progressive pancytopenia.