A model of diamond-like carbon growth in low-pressure plasma reactors using methane as the precursor is presented. The model considers a simplified description of transport phenomena, assuming a well-mixed gas phase and a detailed kinetic mechanism consisting of gas and surface reactions. Rate constants taken from the literature were combined with others calculated using thermochemical methods. The model predicts the film growth rate and its hydrogen content as a function of substrate temperature, pressure, feed flow rate, and applied electric power. Furthermore the catalytic effect of ions on the growing surface is explained, and methyl is identified as the most important precursor to deposition. The results of the simulations were compared with three different plasma reactors described in the literature and characterized by different working conditions : an electron cyclotron resonance reactor and two radio-frequency reactors (with 13.56 and 2.0 MHz discharge frequencies).