Abundant cytoplasmic vacuolation of neuroblasts has been noted on bone marrow aspirate (BMA) smears of two patients with metastatic neuroblastoma. Occasional tumor cells were dispersed as individual cells as well as in clumps. These cells had basophilic cytoplasm and several nucleoli, reminiscent of L3 lymphoblast morphology. Flow cytometric analysis of the bone marrow mononuclear cells and neuron-specific enolase staining of the bone marrow biopsy samples further distinguished the cells as neuroblasts. Cytoplasmic vacuolations of neuroblasts may be a feature of metastatic neuroblastoma cells in BMA smears. Pediatr Blood Cancer 2007;48:227–229. © 2006 Wiley-Liss, Inc.