A large-scale fractionation of poly(vinyl chloride) (3000 g.) has been carried out by a fractional precipitation method. The molecular weight distribution of some fractions has been controlled by refractionation. The fractions have been also characterized by viscometry, osmometry, light-scattering, and glass transition temperature measurements. The data available in literature concerning the molecular weight characterization of poly(vinyl chloride) fractions have been critically reviewed. It has been shown that most of the viscometric and osmometric data are in good agreement when the molecular weights are below 105. Above 105 the literature discrepancies can be attributed to aggregation.