Experimental and numerical results relating to dam-break flows are compared. Dam-break waves were generated by the quasi-instantaneous removal of a plate in a smooth prismatic channel of rectangular cross-section over horizontal dry and wet beds. The laboratory experiments were conducted to determine the initial stages of the free surface profiles using digital image processing. The flow characteristics were detected by applying an adequate, simple and economical measuring technique. The experimental results were compared with the results of a commercially available CFD program, solving the Reynolds-averaged Navier-Stokes (RANS) equations with the k-epsilon turbulence model involving the shallow-water equations. Measured and computed free surface profiles during the initial dam-break stages indicate that although both models predict the dam-break flow with a reasonable accuracy, the agreement using the RANS model is better.