Poly(itaconic acid)(PIA)was obtained indirectly, by the hydrolysis of PIA esters and directly by the polymerization of itaconic acid in water or methanol at 30-degrees-C. The first method was not satisfactory but the second gave better results. The elemental composition of the synthetized samples deviated very little from the calculated values. Several crude polymers were fractionated in methanol/isopropanol and the fractions characterized by viscosity and light scattering. The statistically calculated LVN/M(w) relation,valid for the undissociated polymer, was treated according to the method of Stockmayer and Kurata, to calculate the unperturbed dimensions and to compare them with those of other polymers.