The paper presents a three-dimensional vector propagation model applicable to an indoor wireless communication system, in which the scatterers are grouped into two categories, i.e. deterministic scatterers and randomly distributed scatterers. Exact information on locations and dimensions are used for the former category, while the rest of the scatterers are assumed to be randomly distributed with estimated statistical parameters. The model is based on the uniform theory of diffraction (UTD), multiple-image theory and a ray-launching technique to include all possible reflections and diffractions from ceiling, floor, walls, columns, edges and corners. Theoretical results of the power delay profiles and root-mean-square delay spreads are compared with indoor measurements done in Ottawa and Kyoto published by other authors. The good agreement with these measurements indicates that our model works well for such indoor microcellular communication applications.