Many studies have focused on biofuel development from non-food biomass. Second generation biofuels (2G) manufactured from waste/recycled greases and animal fats are one of the alternatives to the first generation (1G) plant oil-based biofuels. In this study, the 2G biofuel parameter dependence on waste fats' fatty acids profile was examined. The methyl esters parameters included density, viscosity and cold filter plugging point (CFPP); and the biofuels used included waste cooking oil (WCO) and waste animal fat (WAF) obtained through low temperature one step trans-esterification process. Purified and dehydrated samples came from various batches around Poland. Each sample's animal fat content profile was obtained through gas chromatography and acid value method. The fats were transesterifcated at 60 degrees C with methanol 1: 9 (mole/mole) and KOH 1% (m/m) catalyzer. The coefficients of reaction efficiency, viscosity as a function of temperature, density at 15 degrees C and cold filter plugging point were obtained. Their cause and effect dependence on fat acid's content was evaluated based on correlation coefficient (CC) values. The relative standard deviation (RSD) at 38% pointed to nonhomogeneous content of waste fats. The source of fats had no significant influence on the reaction efficiency, with 0.98 +/- 0.015 kg biofuel per 1 kg of waste fat yield. The kinetic viscosity of the biofuels' samples conformed to the EN14214 norm only with two in thirty cases. The dependence of viscosity, density and CFPP on fat acids' profile were confirmed only for a few of studied biofuels. (C) 2017 Elsevier Ltd. All rights reserved.