Composite slabs made of steel and concrete behavior is still today something difficult to predict. The purpose of the current project is to advance in this area with the help of Finite Elements (FE). The complex phenomena of interaction occurring between the steel deck and concrete are modeled using finite elements. Current tests are costly and take a lot of time, as the constructions of the slabs require time and money. Moreover, designing methods based on full-scale specimens proposed by Eurocode 4 [1] introduce parameters that decrease the real resistance on the safe side of the assumption. This fact is translated into a large increase of material and therefore expenses. Furthermore, these methods do not explain accurately the real comportment of these kinds of slabs. This report presents the results obtained of the modeled simulations using FE comparing them with the results of carried out bending tests of slabs of four different commercial steel sheeting profiles tested at “Laboratori d’estructures i resistència de materials” (LERMA) [2] [3] [4] [5] [6] in the UPC. The modeling builds an accurate geometrical model of full scale bending tests with the ability of describing macro and micro behaviors. The project also focuses on the improvement of concrete modeling, tries to explain some behaviors and compare some ranges of geometrical variables while the reliability of the model is contrasted. As a result of the progresses achieved during the development of the project, part of the findings of this research were submitted as article to EUROSTEEL 2014 that will take place in Naples on September [7]. Its full content is presented in the Annex.