Biodiesel was synthesized using waste chicken oil and ethyl alcohol as reactives as well as denatonium benzoate and tin particles as catalysts in 500 mL three neck flask. The reaction mixtures were mechanically stirred at 200 rpm during 15 minutes at 30, 40, 50, y 60 º C, after that the products were filtered trough a 400 m mesh an then casted in a separating funnel in order to obtain two layers corresponding to glycerol and Biodiesel. The tin catalyst particles were observed by optical microscopy. The biodiesel and glycerol were characterized using refractive index, pH, Fourier transformer infrared spectrometry (FTIR), while the viscosity was determined in a Brookfield viscosimeter and density using a picnometer. The results suggest that at a low concentration of denatonuim benzoate (7 ppm) the reaction will occur only if tin is present at all test temperatures. The pH of biodiesel obtained was 6, similar to petrodiesel used commonly in diesel motors.