This study quantified the pollutants in the wastewater (WW) of biodiesel. Density, number of acid, and viscosity were determined for biodiesel quality characteristics. The characterization of the effluents was performed according to the Mexican Environmental Norm. The viscosity was higher than the normalized limit (>5mm(2)/s). The WW had high concentrations of total suspended solids (TSS; >730 mg/l) and fat and oil (>1810 mg/l), the latter with significant differences (P > 0.05), and presented toxicity (>35000 mg/l), due to the presence of oil. Therefore these should not be discharged into the sewage networks or water bodies, considering the possible adverse effects in the environment.