The role of choline in cellular life and its use as a biomarker of different pathologies are reviewed. Choline is an essential nutrient that is crucial for normal cellular function. It is predominantly absorbed from the small intestine. A diet is considered as a major source of choline though it can be produced by cells. Choline in the form of phosphatidylcholine is a very important cell membrane constituent. Choline and its derivatives play an important role in such events as neurotransmitter acetylcholine synthesis, cell-membrane signaling (phospholipids), lipid transport (lipoproteins), and methyl-group metabolism (homocysteine reduction). Choline was considered to be an integral part of folate and methylation pathways. Myocardial and other pathologies may be associated with an alteration of blood choline level that allows considering its application as a biomarker molecule.