The behaviour and characteristics of the elements of prefabricated composite steel and concrete structures are determined by behaviour of the longitudinal shear connection. Headed studs in groups are most frequently used for forming longitudinal shear connection of prefabricated composite beams. The results of experimental research and advanced numerical models of shear connections, obtained using groups of headed studs, are presented in the paper. When headed studs are arranged in groups, it is recommended to use the headed studs with the height greater than the 4d height prescribed by the Eurocode@en