Abstract In the recent years, particular attention was given to the research aimed at optimizing the use of tumour epigenetic markers. One of the best known epigenetic changes associated with the process of carcinogenesis is aberrant DNA methylation. The aim of the present research was to evaluate the methylation profile of genes potentially important in the diagnosis and/or prognosis of equine sarcoids, the most commonly detected skin tumours in Equidae. The methylation status of potential promoter sequences of nine genes: APC, CCND2, CDKN2B, DCC, RARβ, RASSF1, RASSF5, THBS1 and TRPM1, was determined using bisulfite sequencing polymerase chain reaction (BSP-CR). The results of this study did not reveal any changes in the level of DNA methylation in the analysed group of candidate genes between the tumour and healthy tissues. Despite numerous reports describing the aberrant methylation of the promoters of the analysed genes in human cancers, the data obtained did not confirm the existence of such relationships in the examined tumour tissues, which excludes the possibility of using these genes for the diagnosis of the equine sarcoid.