The discovery of the Merkel cell polyomavirus (MCV) in a large number of Merkel cell carcinomas (MCCs) has led to many investigations into its potential role as an oncovirus. Many studies have recently explored the differences between MCCs infected and not infected with MCV.To review the role of MCV in MCC and its potential to influence diagnosis, prognosis, and treatment.An extensive literature search was performed on MCV and its relationship with other polyomaviruses and MCC. The immune system's role in MCC was also investigated.We included 60 articles regarding MCC and MCV and seven pertinent to general processes involved with MCC and MCV.Merkel cell polyomavirus appears to affect many aspects of MCC. An understanding of this virus may aid in future therapy options and current pathology protocols in diagnosing MCC. The host's immune function appears to affect MCV's ability to cause cellular transformation leading to MCC.