Pyrolysis is an effective method of converting agricultural byproducts to a tarry complex fluid suitable for use as a liquid fuel. While superficially similar in appearance to crude petroleum, pyrolysis oil contains significantly more oxygenated and nitrogenous compounds and up to 30% water by mass. These differences in composition affect both the heating value and viscosity of the fuel. We used the reduced-pressure advanced distillation curve (ADC) method to characterize the boiling point and composition of pyrolysis oil derived from swine manure. The swine manure pyrolysis oil was found to contain similar to 15% water by mass. Thermal cracking of the sample was observed near 300 degrees C at 3.5 kPa. The pyrolysis oil viscosity decreases exponentially as a function of temperature from 50 to 75 degrees C. Published by Elsevier Ltd.