Crudes from the Shengli and Tuha oil fields (China) and the PetroKazakhstan oil field (Kazakhstan) containing macromolecular paraffins were investigated by gas chromatography, H-1 NMR spectroscopy, etc. The mechanism of inhibition of the paraffin deposits in the wells in these fields was investigated by microscopic studies and measurement of the contact angle of wetting of steel with water. It was shown that a low content of asphaltenes and resins in the crude, high gas: crude ratio in the field, high molecular weight of the paraffins with low branching of their molecules, and a temperature in the wellhead lower than the initial crystallization temperature of the paraffins are the basic causes of deposition of macromolecular paraffins. The effectiveness of inhibition of paraffin deposits in such crudes is greater than 60%. The mechanism of inhibition consists of preventing formation of a three-dimensional structure in the paraffins and depositing them on the surface by modifying the structure of the paraffin crystals and changing the wettability of the surface of steel with water.