Genetic variability is an essential feature of RNA viruses. It allows them to adapt to the ever-changing environmental conditions. Important biological properties of the viruses, their infectivity, adaptability, and host range, may also depend on the level of quasispecies diversity. Here, we present the analysis of the genetic polymorphism of Pepino mosaic virus (PepMV). The examined populations were isolated from the naturally infected tomato plants (Solanum lycopersicum). In order to determine the complexity of the PepMV populations, the number of different viral variants and their genetic diversity was established. Moreover, phylogenetic trees were created to depict relations between the identified variants. For the first time we have shown that the PepMV exists as a quasispecies. The observed level of genetic variability allows PepMV for a quick and flexible adaptation to different hosts. Our results suggest that the level of PepMV variability possibly influences the course of infection.