We report here there cases of benign parotid gland oncocytoma with pseudomalignant change that mimic acinic cell carcinoma. All patients underwent fine-needle aspiration biopsy of the tumor 62, 725 and 33 days before surgical excision. In histologic sections, there were clusters of pigmented cells with PAS-positive foamy to finely granular cytoplasm similar to those seen in salivary gland acinic cell carcinomas. This report provides another, previously undescribed, example of a diagnostic pitfall that may be observed in histologic tissue specimens removed after FNA of oncocytic tumors.