Among the β + emitting isotopes, produced in medical cyclotrons, carbon-11 is promising radionuclide for labeling of biologically active compounds and tracking their distribution in living organism. Therefore aminoacids, carboxylic acids, fatty acids and amines have been widely used in assessing and staging of brain tumors ( 11 Cmethionine), prostate cancer ( 11 C-choline, 11 C-acetate) and neurological disorders ( 11 C-labeled neurotransmitters). This paper reviews recent achievements in synthesis of endogenous substances labeled with 11 C and presents our experience in 11 C-methionine synthesis. Proposed protocol is a reliable tool for routine manufacturing in clinical applications and animal studies.