Abstract: A method and apparatus particularly adapted for use in continuously testing for leaks in a plurality of generally fluid-tight and flexible packages which are conveyed along a predetermined path. This particular apparatus embodies first means for selectively and continuously conveying a plurality of the packages along the predetermined path, second means operatively connected to the first means for compressing the generally fluid-tight packages as they are continuously conveyed along the predetermined path to the extent that those packages which do not have leaks expand by at least a predetermined amount and whereas those packages which have leaks will not expand by the predetermined amount, and third means being operatively connected to the second means for at least monitoring the existence of the predetermined expanded packages as the packages are continuously advanced to thereby enable defective packages to be eliminated.