Sewage sludge was treated by pyrolysis or by partial combustion, and the effect of treatment on the higher fatty acid content of the tar produced was examined. The energy recovery ratio in these treatments was also calculated by analyzing the gas, char and tar produced. Fatty acid was detected in the tar in high concentration, and 21.42 mg-fatty acid/g-sludge (phenol equivalent) was recovered after partial combustion at 973 K. Under the experimental conditons, 43% of higher fatty acid in dewatered sludge was recovered, of which palmitic acid was the major component of recovered tar.