This review presents basic data describing structure, formation and behaviour of fibrin. Mechanism of fibrin monomer formation and its polymerisation to the fibrin net and its stabilisation are described in detail. Relations between conditions of polymerisation and structure of fibrin are discussed. Significance of fibrinopeptide cleavage and significance of the delay between FPA and FPB cleavage for the formation of well-organised fibrin polymer are explained and emphasised. Moreover, the properties of formed fibrin polymer and its impact on the activity of other reactions are also described.

        Key words: fibrin, fibrinogen, FBN, FBG, FDP, fibrinolysis.