Ultrasonic Backscattered Amplitude Integral (BAI) values are used to detect critical and major defects such as nonbonding, wrinkles and bubbles distributed within the seal area of flexible food packages. The BAI-mode imaging by itself is not capable of detecting such nonbonding, wrinkles and bubbles distributed within Me seal area, For this study, model defects in the seal region of all-plastic and foil-containing films were created by varying Me sealing-bar temperature. Seal regions were scanned by a 17.3-MHz ultrasonic transducer, and the waveform for each scan point was processed by the BAI-mode method. The mean and the coefficient of variation of the BAI values (BAICV) were calculated. It is shown that a combination of mean BAI value and BAICV value can detect defects distributed in seals in flexible food packages. This technique has the potential of providing a real-time, on-line control by sensing whether a proper seal has been achieved.