The aim of this paper is to present a design method based on small scale tests and a finite element analysis called 3P PCSM (three parameters partial connection strength method) for composite slabs with shallow sheeting. A short review of the current design methods in Eurocode 4 (1) are given just to accentuate a new contribution. Distribution of forces within composite slabs for various loading is discussed. A well established definition of the shear length is redefined in the context of the new findings, in Veljkovic (2) and for implementation in the new design method. Finally, an example is given where a design according to 3P PCSM is compared with two methods given in Eurocode 4, the m-k method and the partial connection strength method.