Biodiesels from different sources have received significant interest, driven by concerns over oil price instability, sustainability of energy supplies and measures taken to reduce the increase in greenhouse gas emissions. This study analyzes the environmental performance of biodiesel from leather industry fleshings (BDF) in comparison to biodiesel from vegetable oil (BDV). Life Cycle Assessment (LCA) methodology is used to environmentally evaluate both biofuels and energy return on investment (EROI) based ratio is calculated to evaluate which biodiesel provides more energy compared to the required during its production. Environmental benefits of both biodiesels are evaluated by analyzing the global warming potential impact category defined by CML 2001 (measured in kg of CO2 equivalent emissions). Preliminary results with an EROI increase by nearly 2.4 fold and approximately 85% of GWP reduction for BDF production, show a clear preference for BDF as compared to BDV