The polynuclear manganese(II) complex of L-dihydroorotic acid has been synthesized and characterized by X-ray crystallography, UV-visible spectroscopy, and magnetic susceptibility measurements. Crystal data: triclinic, space groupP1 bar ,a= 4.7239(5) Å,b= 7.902(1) Å,c= 10.552(2) Å, &agr; = 105.80(1)°, &bgr; = 98.864(7)°, &ggr; = 104.69(1)°,V= 355.9(1) D 3,Z= 1,R= 0.035,Rw= 0.028. This complex consists of polymer chains of manganese atoms that are bound together via carboxylate bridges with a Mn...Mn distance in the chain of 4.724 D . The radical scavenging properties of the complex have been evaluated by ESR spectroscopy and cyclic voltammetry methods and compared to those of vitamin E and BHT (2,6-di-tert-butyl-4-methylphenol).Key words: orotic acid, L-dihydroorotic acid, manganese(II) complex, antioxidative properties.