Identification and protection of the facial nerve is very important in the proper operation of the parotid tumor. Posterior approach which finds main trunk of the facial nerve by surgical landmark such as tragal pointer, tympanomastoid suture, and posterior belly of digastric muscle is most commonly used. In case of posterior located tumor, inferior approach may be used, in which the retromandibular vein is followed from the neck and inferior branch of the facial nerve is located. In general, the facial nerve lies superficial to the retromandibular vein. But we experienced the anomalous relationship of the facial nerve and the retromandibular vien. We report this case with a literature review.