Epigallocatechin 3-gallate (EGCG) is an antitumor molecule and shows this activity by binding to the active center of a methyltransferase enzyme (DNMT1). The methylation of DNA sequences of tumor suppressor and DNA repair genes is observed in different stages of carcinogenesis. In this study, we analyzed the effect of EGCG on the methylation status of 25 tumor suppressor genes in cancer cell lines HT-29 and MCF-7. HT-29 and MCF-7 cells were incubated with 10 µM, 20 µM, and 50 µM and 1 µM, 5 µM, and 10 µM EGCG for 48 h, respectively. We found promoter hypermethylation of (1) CDH13, GATA5, and RARβ genes in MCF-7 cell line and (2) RARβ, ESR1, PAX6, WT1, CADM1, CHFR, CDH13, and GATA5 genes in HT-29 cell line. However, (3) after EGCG application, no changes in methylation status were detected in our samples. Our results suggest that methylation status of tumor suppressor genes did not change with different EGCG doses.