This paper presents a novel and efficient hybrid model combining a two-dimensional (2-D) site-specific model and a statistical model to characterize multipath fading in indoor environments. The site-specific model describes the propagation effects of interior walls and building walls. The latter model characterizes the effect of scattering due to rough surface boundaries and/or randomly positioned scatterers such as furniture and personnel, which significantly affects small-scale fading. The hybrid model is computationally efficient since only the 2-D site-specific model is needed. In addition to accurately predicting mean field strength, the model can effectively quantify the relative mean contribution of diffused scattering with a factor r. The factor is also an effective index to quantify the cluttering strength of the propagation environment: 1) light-cluttering situation r ≦ 0.35 and 2) heavy-cluttering situation r ≧ 0.65. Some blind tests validate the effectiveness of the model. A large amount of experimental data for 2.44-GHz radio at many different sites shows that a Nakagami distribution describes the fading distribution well.