LDA measurements and CFD predictions of the flow in a vessel stirred by a retreat curve impeller are reported. The CFD simulation was carried out using a commercial code CFX 5.5.1. The computational results have been extensively validated through the phase-resolved and phase-averaged LDA measurements to avoid the errors associated with pseudo-turbulence. It is shown that the axial and radial velocities were well predicted quantitatively over the whole vessel by the CFD simulation but the predicted tangential and turbulent kinetic energy are less close in agreement with the experimental data.