The hydrodenitrogenation (HDN) reactivity of indole (IND) was determined over a NiMo/Al2O3 catalyst and a CoMo/Al2O3 catalyst using a fixed-bed reactor at 631 K and 3.5 MPa pressure. Conversions and product distribution data were obtained at various feed compositions of indole and space times. The kinetics of the individual steps in the HDN pathways were determined by application of Langmuir-Hinshelwood kinetics to a reaction model proposed by Zhang and Ozkan. All reaction paths were inhibited by indole and three different active sites were required to correlate the data. Under comparable conditions, the CoMo catalyst was more active for the initial conversion of indole, but the NiMo catalyst gave higher HDN conversion. The former catalyst gave higher yields of N-containing intermediates than the latter. An increase in hydrogen sulfide concentration had little effect on the total conversion and decreased the HDN conversion for the NiMo catalyst, whereas total conversion increased while HDN conversion was unaffected for the CoMo catalyst.