L3 morphology according to the FAB classification and the 14q+ chromosome are usually ascribed to the Burkitt type of leukaemia or lymphoma with a B or pre-B cell phenotype. We report here a case of adult acute leukaemia with Burkitt morphology and the 14q+, which did not express lymphoid markers. Instead, the leukaemia was shown to be an acute erythroleukaemia. The erythrocyte marker glycophorin A was present on the surface of the leukemic blasts as shown by immunofluorescence and immunoprecipitation from membrane lysates of surface labeled cells with antiglycophorin A antiserum. Spectrin and fetal hemoglobin appeared after cultivation of the blasts in the presence of sodium butyrate. The present case shows that a short term cultivation is sometimes useful for further characterization of the commitment of acute leukaemias.