Several types of economical and effective connectors are commonly used for composite steel and concrete beams at present. Perforated shear connector has been developed during last two decades and have become popular due to their advantageous properties. At the Department of Steel and Timber Structures of CTU many experiments (push-out test) were carried out with two types of connector with different openings, various strengths of concrete and amount of reinforcement. The design formulas for static shear load capacity were deduced on the basis of these experiments. Nowadays, small modification of basic connector was designed for decrease of laboriousness in situ. Results of modified connector are in good compare with previous one.