In this paper results of the experimental tests of four full-scale composite steel-concrete elements are reported. In the steel-concrete composite elements, a steel beam was connected with a slab cast on profiled sheeting, by shear studs. The end-plates were (the thickness of 8 mm, 10 mm and 12 mm) thinner than in ordinary design. Joints between the column and the beams have been designed as semi-rigid, i.e. the deformations of endplates affect the distribution of forces in the adjacent parts of the slab. The paper presents the theory of cracking in reinforced concrete and steel-concrete composite members (according to the codes), view of crack pattern on the surface of the slabs and a comparison of the tests results and the code calculations. It was observed, that some factors influencing on crack widths are not taken in Eurocode 4 (which is based on Eurocode 2 with taking into account the phenomenon called „tension stiffening”).