[en] The method of measuring proper resolution of organic scintillators, based on principles applied in detectors with inorganic scintillators, is described. The measurement of photomultiplier and detector contributions to the apparatus resolution is performed both for scintillators based on NaI(Tl) with a photopeak, and for scintillators based on polysterine of the standard composition with a Compton spectrum only. The method for detector on the base of potysterine (the cytinder with the height and diameter 150 mm) the surface of which is painted with white diffusion reflecting paint gives the value of proper resolution 8.63% at the static error 0.45%