Abstract: A method and apparatus for inspecting the bottom of a transparent container for defective conditions, such as internal stuck glass, internal loose glass or foreign material. The container is provided in an inspection zone and a linearly extending line of light from a light source is focused to pass through the container bottom with the line of light extending the length of the inspection zone and hence the length of the container bottom. The linearly extending line of light enters the container through the exterior surface of the container bottom. The intensity of the light reflected from defects in or within the container and through the container side wall at a predetermined angle is detected. The detected intensity of the reflected light is compared with a predetermined threshold value that provides a measure of the acceptability of the container.