Cancers of unknown primary origin (CUP) account for 0.5-10% of all malignancies. CUP patients with metastases have a median survival of approximately 6 months, despite therapy. Identification of the primary tumour site may offer the opportunity of a specific and more efficient treatment. The case of a 45-year-old woman with supraclavicular lymph node metastases of a squamous cell CUP is reported. A staging laparoscopy with multiple biopsies and a loop diathermy excision of the cervix were performed. Human papillomavirus (HPV)-testing in the tissues revealed the tumour cells as metastases of an occult cervical cancer. Primary platin-based chemotherapy combined with paclitaxel leads to a complete apparative remission. Twelve months later, staging positron emission tomography with 2-[18F]fluoro-2-deoxy-D-glucose in combination with computed tomography identified an isolated left renal lymph node metastasis. The patient received targeted radiation therapy, combined with cisplatin. To date, 19 months after diagnosis, she is doing well without any evidence of disease. The presented case report addresses the difficulties involving the identification of CUP. HPV-DNA is found in over 95% of cervical cancers. As the presented case illustrates, testing for this virus DNA in human tissues can be a useful diagnostic tool in patients with CUP where cervical cancer is the possible primary tumour.