Abstract: A system for automatically detecting sidewall and dimensional defects in a transparent container includes a laser scanning system positioned astride a conveyor in a production line. In an upstream inspection zone a laser beam vertically scans a portion of the side wall of the container. Photosensors positioned in a detection chamber detect the specific effect which any defect has upon the laser beam by determining the location of light passing through the container and comparing its intensity against pre-set thresholds. A flaw signal is generated when a threshold is exceeded. The number of flaw signals is counted and when the count equals a pre-set value a reject signal is generated to eject the defective container from the conveyor. If a container is not rejected, it passes through a rotator assembly which rotates the container precisely 90.degree..