Abstract The paper contains a numerical analysis of a steel-concrete composite beam with a composite dowel. The connector is a contoured part of the web in a half of the steel section. In the first part of the work, the composite beam was analytically designed in accordance with PN-EN 1994-1-1 standard. Three cross-sections were selected from a hot-rolled sections 1/2 HEB 600, 1/2 HEA 500 and 1/2 HEA 400, so that the beams effort was 50%, 70% and 90% respectively. The length of the beam was 6.0 m. Structural steel S235, reinforcement steel f yk = 500 MPa (B500B) and concrete C20/25, C25/30, C30/37 were used. In the second part of the work the numerical analysis was carried out using the ADINA System program based on the Finite Element Method . The shape of the composite dowels in the class from the concrete class was optimized. The influence of the composite dowels shape on the stress concentration in the area of the composite dowels depending on the beam effort was considered. The stresses and displacements in the steel and concrete parts as well as cracking in concrete were assessed.