The case of a 23-year-old male with a solitary prostatic metastasis of a small cell lung cancer is reported. After diagnosis was established by ultrasound-guided transrectal biopsies and bronchial lavage, the patient received 7 cycles of polychemotherapy according to the AEO protocol. While the pulmonary tumour responded with a dramatic remission, the size of the prostatic metastasis remained unchanged. Subsequent radiotherapy to the prostate and pelvis (59 Gy) did not result in tumour reduction. Shortly thereafter, the patient developed polytopic metastases and died 16 months after diagnosis. Even in a young male, the presence of a prostatic metastasis should be considered as a potential diagnosis if prostate biopsies are positive for a small cell carcinoma.