The objective of the study was to determine global DNA methylation induced by lengths of exposure to ozone in Candida albicans isolates of human and animal origin. The level of global DNA methylation was tested as the relative methylation level in the samples in relation to a methylated control. The analysis revealed differences in the methylation level in the human and animal samples. Ozone had a significant effect on the DNA methylation process, and longer exposure substantially increased the level of total methylated DNA. As expected, the degree of methylation depended on the length of exposure to ozone.