The capability of the commercial CFD package Fluent to modelling of cyclonic dedusters is investigated. For simulations, appropriate turbulence models were chosen based on a thorough analyses of their structure and literature recommendations for cyclones. To describe a two-phase gas-solid flow, the Eulerian mixture model or Lagrangian discrete phase model, both embedded in the software code, were applied. Based on these results of calculations, the pressure drop and collecting efficiency of solid particles were evaluated, and compared with literature date as well as with predictions of simple empirical and semi-empirical models, which are widely used in engineering practice for designing cyclonic separators.