Spontaneous seminoma was experienced in an old male black swan. Two solid neoplastic masses 10×5×5 and 6×5×5cm in diameter were found attached to the body cavity wall at a level of the 6th and 7th thoracic vertebrae. Neoplastic cells were proliferated in the seminiferous tubules with infiltration into the right kidney parenchyma which was fused with a tumor. Metastatic foci were observed in the liver.