In this paper, the process of seeded granulation in a high shear mixer is simulated by the discrete element method (DEM). A 5. litre Cyclomix granulator manufactured by Hosokawa Micron B.V. was simulated at different impeller rotational speeds. It has been observed that the seeded granules form by a continuous growth and reduction in size during the granulation process. Quantitative analysis shows that in general a higher number of seeded granules form at lower impeller rotational speeds; however it is found that for all the seeded granules the seed surface coverage by fines is from 5 to 60. Further analyses revealed that seeded granules with the seed surface coverage higher than 50 are more frequently formed at high impeller rotational speeds. The work demonstrates the capability of DEM for modelling granulation processes, as a tool to explore the underlying mechanisms of granulation in general and seeded granulation in particular. © 2012 Elsevier B.V.