We present the first dedicated case series of bilateral synchronous tonsillar carcinoma and discuss the role of bilateral tonsillectomy as a diagnostic tool. The occurrence of multiple head and neck tumours is well recognised; however, reports of bilateral synchronous tonsillar carcinoma are rare. A literature review reveals only 12 cases of bilateral synchronous tonsillar carcinoma described in the international literature in the past 15 years. We present a further three cases confirmed following bilateral tonsillectomy. In conclusion, bilateral tonsillectomy has in many centres been established as a standard diagnostic and therapeutic procedure for patients who have cervical metastases from a head and neck cancer of unknown primary site. It is likely the true incidence of bilateral synchronous tonsillar carcinoma is underestimated and under-reported. We recommend bilateral tonsillectomy for patients with suspected or proven unilateral tonsillar carcinoma as well as those with cervical metastases from unknown primary site.