Abstract: A method for detection and identification of defects in a weld seam created using a laser beam. According to this method, at least two measurement signals are acquired in real time delivered by optical sensors (C1 to C6) detecting variations in luminous intensity of the plasma formed by the laser beam (14). These signals are then combined by applying a mathematical operation. The combined signal obtained is then compared to a predetermined threshold. Depending on the result of this comparison, a determination is made of the presence or absence of a defect corresponding to the operator used.