The traditional analysis methods recommended by design codes such as ACI 318-95 (Building 1995), BS 8110 (structural 1997) and ECP 203 ‘Egyptian code (2007)' allow the ribbed slab to be analyzed in accordance with the rules for solid slab or as the plain flat slab. The traditional method doesn't take into consideration a lot of factors in the analysis such as thickness of slab and depth of the ribs. The ribbed slabs were analyzed in this study using the finite element method through SAP 2000 program. The structure was analyzed as oneunit in two dimensions x and y. This study included one way and two way slabs. This study illustrated the difference in the produced internal forces in the ribs between traditional method and the finite element method. Moreover, this study included the investigation of the factors which aren't taken into account in the traditional method. These factors were the connection between the rib and the supported beam, the effect of solid part on the behavior of rib, the effect of the edge beams on the distribution loads on ribs, the effect of cross ribs, the effect of slab thickness, the effect of the depth of rib, the effect of slab width and the effect of the location of rib.