AbstractPoly(vinyl chloride) of low molecular weight (the fraction extracted with a hexane/acetone mixture (vol.‐ratio 3:2)) was substituted by hydroxyphenyl groups and then analyzed by1H NMR spectroscopy. It was established that the1H NMR spectra of hydroxyphenyl substituted poly(vinyl chloride) prepared by removal of HCl, allows to determine the number of unsaturated end groups and to distinguish between the structures CHClCH2CHCHCH2Cl and CH2CHClCHCHCH2Cl, and even between their trans and cis forms. In addition the1H NMR spectra of hydroxyphenyl substituted poly(vinyl chloride) prepared without removal of HCl allow to determine the total number of u