Tests have been carried out to study the influence of surface reinforcement on the load bearing capacity of cast-in headed bars. In 66 tests, rods with a diameter of Φ30 mm and a Φ45 mm nut at the end, were cast-in place centrically in concrete slabs. Width, length and thickness of the slabs varied from 1.2 m × 1.2 m × 0.3 m up to 2.2 m × 2.2 m × 0.6 m. The top reinforcement varied from 0% to about 1.2% (Φ 16 #100). A considerable increase in the load-bearing capacity was noted. The increase depends on the geometry and the amount and placement of the reinforcement. A numerical model to evaluate the influence is proposed.