To assess the quality of panoramic radiographs in a sample of general dental practices, to determine the relative frequency of errors and to identify those errors directly responsible for diagnostically inadequate images. Examination of 1,813 panoramic radiographs obtained from 41 general dental practitioners and recording of faults. The study was carried out in 1998. Radiographs were judged as being 'excellent', 'diagnostically acceptable' or 'unacceptable'. Only 0.8% of films were 'excellent', 66.2% were 'diagnostically acceptable' and 33% were 'unacceptable'. The most common faults which directly contributed to failure of the radiographs were antero-posterior positioning errors, low density and low contrast. The quality of panoramic radiographs was considerably lower than standards recently set for primary dental care. The quality of panoramic radiography could be improved by careful attention to radiographic technique and processing.