One of the main drawbacks of the use of biodiesel is its bad behavior at low temperatures. In this work, we show that it is possible to take profit of the presence of free fatty acids in the starting materials used for biodiesel production (i.e. reused oils) by synthesizing additives able to improve cold flow properties. The synthesis of fatty acid derivatives have been successfully carried out by esterification of stearic, oleic and linoleic acids with bulky linear and cyclic alcohols and by epoxidation of methyl oleate and subsequent ring-opening reaction with the same alcohols. The study of crystallization patterns of pure derivatives by DSC and optical microscopy revealed the improvement of cold properties of biodiesel. Blends of biodiesel with up to 5% of some of these compounds allowed a decrease of CFPP (Cold Filter Pour Point). Both observations reveal the utility of these compounds as cheap and renewable additives. (C) 2010 Elsevier Ltd. All rights reserved.