The authors present the histological and cytological features of bone marrow (BM) in 152 employees from the steel plant of Cubatão (S. Paulo-Brazil) who presented with neutropenia, due to chronic exposure to benzene and its homologues. All patients were male. Mean age was 35 years. At the time of this study, all patients were removed from risk areas because of the hematological abnormality. BM morphology was characterized by a hypocellular hemopoiesis (82%). Decrease of the granulocytic precursors (86%) was the most outstanding feature. Erythroid and megakaryocytic series were diminished in 40% and 57% of the cases, respectively. Eosinophilia in BM was observed in 71% of the cases. Cell atypias and stromal changes (necrosis, increase in reticulin fibres) were frequent.