Merkel cell carcinoma of the genitalia is very rare and to date has been found only in vulvar mucosa. We describe an aggressive Merkel cell tumor in the frenulum of the penis with lymph node metastases, local recurrence, and eventually widespread dissemination. The primary tumor was associated with discontiguous squamous cell carcinoma in situ. This is the first report of Merkel cell (neuroendocrine) carcinoma in this anatomic site.