Abstract: A method for marking, at the outlet of a forming machine using a laser beam, a marking area on hot glass containers comprises determining the longitudinal and transverse positions of the marking area of each container by positioning a first optical axis of a first light sensor and a second optical axis of a second light sensor in a non-parallel manner to each other, in a detection plane parallel to the conveying plane of the containers, detecting the instant of intersection or disengagement, by a container, of the first optical axis and the instant of intersection or disengagement, by a container, of the second optical axis, and calculating said transverse and longitudinal positions from these instants and in consideration of a known or constant speed of translation of the containers. The method can determine the marking instant for each container running past the laser apparatus.