The objective of this research is to model the appearance and behavior of combustion-generated ions in hydrocarbon flames. An understanding of ionic phenomena is important to the development of advanced combustion technology including electrical control of flame structure and suppression of soot formation. Computer models have been developed to evaluate the formation and behavior of ions in acetylene flames;The results of computations are compared to experimental data of other researchers. Several important qualitative features have been successfully modeled. Peak ion concentrations of 10('9) to 10('11) cm('-3) are consistent with experimental measurements. The ratio of large ions to small ions increases sharply as the flame is made richer. The build-up and decay rates of ions observed experimentally are predicted by the model.