A study of the effect of certain operating variables upon the products of pyrolysis of Texas lignite has been undertaken to determine if changes in heating rate, carrier gas flow rate, and particle size can affect the yields and composition of pyrolysis products. Slow heating rates (e.g., 3°C/minute), such as occur during underground coal gasification, were used in all experiments. Data for the pyrolysis of a Milam County (Texas) lignite in an inert nitrogen atmosphere were taken from 25 C to a final char temperature of 900°C. These data showed that the carrier gas flow rate and particle size had very little effect upon the products obtained from pyrolysis of the sample. However, healing rate did have an effect. The average results are in good agreement with similar investigations by the U.S. Bureau of Mines.