The study aimed to compare the sensitivity and specificity of digital radiographic systems for the diagnosis of proximal carious lesions. Extracted human teeth (3 canines, 3 premolars, and 3 molars) were submitted to one of three types of proximal lesions (demineralized area, cavity affecting the enamel alone, and cavity affecting enamel and dentin). Bitewing radiographs were obtained from each system (Sirona, Kodak, and Schick) and evaluated by 12 raters (4 dental students, 4 radiology specialists, and 4 dentists). The chi-squared test was used to determine the frequency of correct diagnoses among the different systems, raters, teeth, and types of lesion. Sensitivity and specificity regarding demineralized areas were calculated for each system. The frequencies of correct diagnoses were found: Schick (70.8%), Kodak (63.9%), Sirona (59.0%), specialists (69.4%), students (62.5%), dentists (61.8%), premolars (70.1%), canines (65.3%), and molars (58.3%). No significant differences were found among the different systems, raters, or teeth (P > 0.05). Sensitivity and specificity were 0.64 and 0.47 (Schick), 0.56 and 0.50 (Sirona), and 0.48 and 0.58 (Kodak). The most correct diagnoses were achieved using the Schick digital system on premolars and evaluated by specialists in radiology. The systems demonstrated low sensitivity and specificity for the diagnosis of demineralized areas.