The use of diesel fuel remains prevalent despite advances in renewable resources. Fatty acid esters derived from plants or animals are being considered as an alternative fuel source, improving combustion and reducing emissions. However, limitations exist in cold climates due to crystallization of paraffins in the fuel. The study investigated the impact of a composite additive made from alpha-olefins maleic anhydride copolymers and ethylene vinyl acetate copolymers on the cold flow properties and crystallization process of biodiesel components. Base fuels and bio-additives were analyzed to determine their physicochemical characteristics and composition. The cold flow properties were evaluated using cold filter plugging point and optical microscopy. Bio-additives were found to increase the effectiveness of the depressor additive, with this effect being more significant for fuels with high cold filter plugging temperature and non-uniform distribution of n-paraffins. We also found that the introduction of waste cooking oil esters better reduced the cold filter plugging temperature due to the higher saturated FAE content in its composition. In addition to this the introduction of the bio-additive significantly changes the size of paraffin crystals formed during fuel cooling, and it is probably due to this effect that the positive impact of fatty acid esters on the cold flow properties of fuels is observed.