We encountered an 81-year-old Japanese man with oncocytoma of the parotid gland occurring simultaneously with a Warthin's tumor in the ipsilateral parotid gland. The patient complained of swelling in the right infra-auricular region. Computed tomographic images, magnetic resonance images, and ultrasonography showed two masses in the right parotid gland. Technetium 99m pertechnetate scintigraphy revealed a high accumulation in both tumors. We performed a superficial lobectomy of the parotid gland. Preoperative diagnosis was multiple Warthin's tumor, but upon histopathological examination Warthin's tumor proved to coexist with oncocytoma. In general, the presence of synchronous, major, salivary gland tumors with different histopathology in the ipsilateral parotid gland appears to be unique. This is especially true for the combination of oncocytomas and Warthin's tumors, which is extremely rare. Only eight cases of this kind coincidence were found in our review of the literature. The similarity of oncocytomas and Warthin's tumors based on epidemiology, image diagnostics, and histopathology is discussed.