Merkel cell carcinoma (MCC) is an aggressive skin cancer that develops in individuals who are over the age of 50 or immunosuppressed. DNA from a new polyomavirus, MCPyV, was recently shown to be clonally integrated in several MCC cases. In this issue, Becker et al. demonstrate that MCPyV DNA can be isolated from 85% of primary European MCC specimens and their metastases, and Garneski et al. present data indicating that the percentage of Australian MCC cases containing MCPyV may be lower than that of North American cases. These reports support the possibility that MCPyV is etiologically involved in at least some cases of MCC.