Background: It was shown by several studies that titanium dioxide nanoparticles (TiO2 NPs) can change the global and gene-specific patterns of DNA methylation. This may result in modifications to the DNA methylation pattern by affecting the expression of DNA methyltransferases (DNMTs). Aim of the work: Evaluation of the epigenetic changes of the genome (DNA methylation) resulting from exposure to TiO2 NPs. Material and methods: Human epithelial adenocarcinoma cell line (CaCo-2 cells) was divided into group 1: untreated cells, group 2: treated with 0.5 % dimethyl sulfoxide, group 3: treated with 100 µg/mL TiO2 NPs for 72 hours, group 4: treated with doxorubicin 30 microgram/ml. The cell line was subjected to cytotoxicity assessment, translocation of TiO2 NPs by transmission electron microscopy (TEM), global DNA methylation quantification, and quantitative measurement of DNMT1, 3A, and 3B gene expression by reverse transcription-PCR. Results: A dose-dependent cytotoxicity was found. TEM revealed the presence of TiO2 NPs within the cells in group 3. DNA methylation showed a significant decrease in groups 3 and 4 than group 1 and group 2. Expression levels of DNMT1 gene showed a significant increase in groups 3 and 4 when comparing them to group 1 and group 2. The expression levels of DNMT3A gene and DNMT3B gene showed a significant decrease in groups 3 and 4 in comparing them to groups 1 and 2. Conclusion: In Caco-2 cells, being exposed to TiO2 NPs can affect DNA methylation, indicating that the toxicity of TiO2 NPs may be related to this epigenetic pathway.