The composition and viscosity-temperature properties of waxy, high-resin crude oil treated in ultrasonic field have been studied by gas chromatography-mass spectrometry, IR and H-1 NMR spectroscopy, and rotational viscometry techniques. It has been shown that the ultrasonic treatment leads to an increase in the proportion of lower n-alkanes in the oil fraction of the treated crude and a reduction in viscosity and the pour point of the crude oil.