This research seeks to optimize and characterize the liquid product obtained from the waste expanded polystyrene (EPS) pyrolysis. Statistical analysis of the experimental results of EPS pyrolysis was developed. A maximum yield of the liquid product was obtained at a temperature of 550 °C and an average particle size of 7.5 mm. Likewise, the total sulfur content, ASTM distillation, API Gravity and density were determined for the liquid product obtained under optimal conditions. Other physicochemical properties were estimated, concluding that the liquid product is similar to synthetic crude.