Protein N-myristoylation is a ubiquitous cotranslational and posttranslational modification catalyzed by myristoyl CoA:protein N-myristoyltransferase (NMT), which attaches myristate, a rare 14-carbon saturated fatty acid, to an N-terminal glycine of some eukaryotic and virus proteins. This protein modification triggers dynamic protein-protein and protein-membrane interactions implicated in diverse physiological processes. This review summarizes the NMT catalytic mechanism and demyristoylation. Of special interest are the primary roles of N-myristoylated protein in signaling, protein targeting, tumorigenesis, apoptosis, virus assembly, and morphology change, as well as the regulation of N-myristoylation and NMT inhibitors.