In addition to panendoscopy and imaging for staging, ipsilateral tonsillectomy is a standard procedure in the search for the primary tumor in cervical cancer of unknown primary site (CUPS). It is not clear from the literature, whether bilateral tonsillectomy has been established as the standard procedure in cancer of unknown primary origin. A bilateral synchronous tonsillar carcinoma has thus far only been described three times in the literature. We report on a case of CUPS in which a bilateral tonsillar carcinoma was detected after bilateral tonsillectomy. We also discuss the inclusion of bilateral tonsillectomy as a standard procedure in the search for primary malignancies. To diagnose and adequately treat a bilateral synchronous tonsillar carcinoma without losing time, we recommend bilateral tonsillectomy as a standard procedure in cervical CUPS.