Abstract. The use of biodiesel from Tilapia visceral oil will allow the development of economy where a fishery is developed. The fishing industry has resulted in the production of large quantities of fish waste, especially fish viscera which are discarded into the environment. The aim of this work is to show the process of Tilapia visceral oil extraction, characterization and obtainment of biodiesel by ethylic route. For the feasibility of transesterification is necessary that the oil has low moisture content and free fatty acids (FFA) below 5%, since the high value of these two parameters can preclude transesterification by forming high quantities of soap. The results of this study show that the Tilapia visceral oil has low moisture (0,12%) and only 3.11% of FFA. For the experiment it was used 1.8% of catalyst KOH, obtaining a high yield of biodiesel as shown by nuclear proton 1 H NMR analysis. The results are very promising and show that it's possible to convert a fish waste in biodiesel.