Catalytic fast pyrolysis of sewage sludge was conducted considering the effects of pyrolysis temperature, atmospheres and catalysts on carbon and nitrogen distributions using a fixed-bed reactor. H-2 atmosphere gave the lowest carbon selectivity of solid products and highest gaseous products yield over HZSM-5 (HZ) at the same temperature compared to Ar and steam. Higher temperature led to an increase in the carbon selectivity of gaseous products and a decrease in the carbon selectivity of solids. H-2 increased the carbon yield of light aromatics (LAs), whereas steam reduced the generation of LAs. Over 0.5Ni-HZ, H-2 gave the highest LAs carbon yield of 11.4%, compared to 1.6% obtained from noncatalytic fast pyrolysis of SS. Higher temperature, H-2 and steam atmospheres, and metal-loaded HZ promoted the transfer of nitrogen into gaseous products. The highest nitrogen yield of NH3 of 55.6% was obtained from sludge pyrolysis over HZ at 700 degrees C under H-2 atmosphere.