This study experimentally and numerically examines the 3D effect on the performance of an open refrigerated display cases (ORDC). Three dimensional simulation model with k-ε-E turbulence model incorpating the buoyancy effect is carried out to compare with the results by 2D simulation model. It is found that the infiltration rate of 3D simulation is significantly larger than that of 2D simulation, indicating the importance of 3D flow field, and it should not be neglected in CFD analysis of an ORDC. The simulation also suggests that turbulence intensity cast a considerable influence on the performance of ORDC. When the turbulence intensity is reduced from 25% to 5%, the temperature difference between the first and the sixth shelf can be reduced from 11°C to 5°C (19.8°F to 9°F) and the infiltration rate can be reduced by 25percent. The 3D computations in terms of temperature distribution inside the shelves were compared with the measurements, and good agreement are reported.