Abstract: A diesel fuel formulation is disclosed containing a water-in-fuel emulsion of (a) a Fischer-Tropsch derived gas oil, optionally in combination with conventional diesel, (b) a fatty acid alkyl ester in an amount of at least 1% v/v and (c) water. An emulsifier may be present. Formulations have useful emissions properties and retain performance characteristics in spite of the presence of water. Methods of preparing the formulations and their uses are also described.