This work seeks to characterize halon replacement combustion byproduct formation mechanisms and chemical kinetics. Experimental studies of inhibited, premixed, one-dimensional flames are described. Microprobe sampling mass spectrometer, thermocouple, and laser induced fluorescence diagnostics are used to measure temperature and chemical species concentration profiles. The effects of 0.33% iodotrifluoromethane and 0.24% perfluoropropane on a 40.0 torr stoichiometric methane/air flame are investigated. Experimental results are compared to a premixed, one-dimensional, laminar flame model. The chemical kinetics model was developed independently of the experimental data and combines the GRI methane oxidation mechanism with a halogen reaction mechanism developed from previous work on CF3Br flame suppression by Westbrook (1983) and Babushok et al. (1994). The model predicts essentially complete combustion of the iodotrifluoromethane and perfluoropropane with hydrofluoric acid as the primary halogenated product. In,addition, iodotrifluoromethane is predicted to generate iodine atoms early in the flame zone. The experimental stable chemical species concentrations profiles show qualitative agreement with the calculated values.