A model for filamentary conduction in RRAMs based on Metal-Insulator-Metal (MIM) structures has been developed. The model describes RRAM resistive switching processes by calculating the formation and rupture of conductive filaments (CFs) in the dielectric. The resistance of the electrodes, of the CF and the hopping current in the gap between the CF tip and the electrode, are taken into consideration. The thermal description of the CF is included by solving the heat equation. The model has been employed to reproduce I–V curves of different RRAM technologies making use of the correct model parameters in each case. Therefore, it is suitable to be implemented in circuit simulators to analyze circuits based on RRAMs under different operation regimes.