To optimize the hydraulic efficiency of sewers or storm water drainage systems, it is necessary to trap the flowing sediments at suitable channel sections using a number of available means. Invert trap is one of the many available means used for trapping the flowing sediments. To analyze the effect of different parameters on the trap efficiency of an invert trap, experimentation is required. As experimentation is always not possible or becomes a costly affair, computational fluid dynamics (CFD) has now become an excellent useful and less expensive tool for the study of flow in sewers and storm water drainage systems. In the present study, a 2D-CFD analysis with volume of fluid (VOF) model, using ANSYSFluent14.0 software, has been performed to predict the trap efficiency of the invert trap for varying flow, particle, and geometrical parameters. The analysis shows that the CFD-VOF model predicts excellent trap efficiency for glass beads of 0.3mm diameter as compared to the experimental trap efficiency of Thinglas (2008) with mean absolute percentage error (MAPE) of 5.54%, whereas it predicted higher trap efficiencies for sand particles of diameter equal (=d(50)) to 0.15mm for which the numerically justified reasons are stated.