Genomewide mapping of posttranscriptional modification in eukaryotic RNA allowed to reveal tens of thousands modification sites. Among modified nucleotides of eukaryotic RNA 6-methyladenosine, 5-methylcytidine, pseudouridine, inosine, and others. Many modification sites are conserved, many are regulated. Function is known for a small subset of modified nucleotides, while the role of majority of them is still obscure. Global character of mRNA modifications allowed scientists to coin a new term, RNA epigenetics. The review is about posttranscriptional messenger RNA modifications in eukaryotes. Main modifications, their role in cell, their mapping techniques and proteins, that are responsible for such RNA modifications are observed.