Abstract: Reinforcement fiber made of metal for the reinforcement of concrete, consisting of a wire piece, which is deformed near both ends over a certain distance. The wire piece, is undeformed between the ends and the deformed part. The two extremities of the reinforcement fiber are not deformed over a distance of 1 to 5 mm. The reinforcement fiber is provided with a profiling consisting of a large number of small notches or grooves. The grooves are provided at an angle to the longitudinal axis of the reinforcement fiber. The length of the reinforcement fiber lies between 10 and 70 mm, and the fibers have a length-thickness ratio of between 40 and 70. The ends of the reinforcement fiber are bevelled at an angle of approximately 45 degrees and are slightly flattened. The transition from the deformed part to the undeformed part is provided with a slight bulge.