Although identifications by this method have been accepted as admissible in court, no tests have been performed to determine the reliability of frontal sinus identification, and no error rate has been estimated. Also, there are no professional standards for the application of the technique. In addition, the visual comparison method is largely subjective, based on the knowledge, experience, or skill of the examiner. This paper describes the materials and methods used to determine the reliability of using frontal sinus radiographs to confirm the identity of a body. This encompasses a description of the sample of skulls used in the study; the method used to take radiographs of the skulls; the obtaining of outlines, coordinates, and EFA coefficients for the frontal sinuses; and the computation of likelihood ratios and posterior probabilities. The paper reports that the results of the research quantitatively support previous notions of the individualized quality of frontal sinus outlines and their reliability in forensic identification; however, the results present a conservative estimate of reliability. The method of comparing frontal sinus radiographs is dependent on the accuracy and availability of hospital and/or mortuary records; inadequate, unreliable, or unavailable antemortem or postmortem data can impede this identification method. Further, the author advises that even if a record of a cranial radiograph is available for comparison, it may still not be applicable for identification for a number of reasons cited. 3 figures, 3 tables, and 28 references