Pulmonary blastoma is a rare lung tumor composed of epithelial and mesenchymal element : the latter element may show various pattern of differentiation toward mature tissue, such as cartilage, smooth muscle, and bone. Rhabdomyoblastic differentiation in pulmonary blastoma is quire rare. In th literature, only seven cases have been reported. We report a case of pulmonary blastoma with rhabdomyoblastic differentiation which occured in a 3 year old girl. Microscopically, cytoplasmic cross-striation was present. Immunohistochemically, strong positivity for vimentin and desmin was observed. Electron microscopy demonstrated A and I bands which documented rhabdomyoblastic differentiation.