Although grapevine leafroll-associated virus 1 (GLRaV-1) is one of the most important agents of the grapevine leafroll disease, the data about its molecular variability are scarce. In order to assess the GLRaV-1 diversity in Slovakia, the sequence of a genome region encoding the central part of the capsid protein (CP) gene was determined from 18 GLRaV-1 isolates. Despite the fact that the analysis targeted a relatively short portion of the genome, comparison of obtained sequences has revealed the nucleotide identities between Slovak isolates ranging from 83.0-100%. Phylogenetic analysis indicated the presence of two distinct molecular groups of GLRaV-1 in Slovakia.