Copolymers of ethylene and propylene, patented by a number of leading foreign firms, are widely used as pour depressants for improving the low-temperature properties of diesel fuel and manufacture of winter grades. Their number-average molecular weight is from 1000 to 3000 and the polydispersity index is from 1.5 to 3. Low-molecular-weight copolymers of ethylene and propylene with different properties were manufactured and their molecular characteristics and depressant properties with respect to diesel fuel are compared in the present study.