Turbulence analysis of flow inside a hydrocyclone is carried out using commercially available CFD software ANSYS CFX (release 11.0) (ANSYS Inc., 2007). CFD software(s) and their turbulence models have come a long way in accurately predicting the flow inside a hydrocyclone. This paper shows, among various turbulence models tested, a two-equation Shear Stress Transport (SST) turbulence model coupled with curvature correction can accurately predict the mean flow behaviour. The same level of accuracy was only found with a SSG Reynolds stress model with a penalty of solving an additional five transport equations. Experimental data of Hsieh (1988) and Monredon et al. (1992) was used to validate our CFD models.