Methylation of tRNA is an important post-transcriptional modification and aberrations in tRNA modification has been implicated in cancer. The DNMT2 enzyme methylates C38 of tRNA-Asp and other tRNAs and it has a role in cellular physiology and stress response and its expression levels are altered in cancer tissues. In this manuscript we studied whether DNMT2 somatic mutations found in cancer tissues affect the catalytic activity of the enzyme. We have generated 13 DNMT2 variants and investigated the corresponding proteins. One of the mutations caused a twofold increase in activity, two of them led to a strong decrease in activity and two additional mutant proteins were almost inactive. This strong effect of some of the somatic cancer mutations on DNMT2 activity suggests that these exchanges have a functional role in tumorigenesis.