A number of alkyl fumarate-vinyl acetate copolymers having a wide range of molecular weights were prepared by solution polymerization using a variety of solvents. The efficacy of these copolymers as flow improvers (FI)/pour point depressants (PPD) was tested on Indian crude oils having similar wax (< 12%) and asphaltene (< 0.5%) contents. The results indicate that the performance of the additives is dependent on the molecular weight of the polymer. The highest molecular weight copolymer is the best additive for crude oils that have a broad range of normal paraffins and lower average carbon numbers. The addition of the lowest molecular weight copolymer resulted in the best efficacy for crude oils containing a narrow range of normal paraffins with higher average carbon numbers. Intermediate molecular weight copolymers are best for crude oils containing a broad range of normal paraffins and higher average carbon number. The peak shear stress and steady shear stress of gelled Bombay High (BH) crude oil (at 16 degrees C) gave a high peak shear stress, which can be reduced by inclusion of surface active agents without affecting the overall rheology of the treated crude oil.