Statement of Problem: Dental caries is the most common chronic infectious diseases involving about 95% of population and still is a major cause of loss of teeth. Dental caries diagnosis is a challenging task for dental practitioners. In spite of developing different diagnostic methods for better evaluation of dental caries, conventional intraoral films continues to be the most widely used radiographic modality for the diagnosis of dental caries.Purpose: The aim of this study was to evaluate the efficiency of Ekta speed plus, insight radiographic films, and RVG ui 100 in detecting proximal caries lesions.Materials and Methods: Seventy two surfaces of 36 extracted human premolars were evaluated. Radiographs of teeth blocks were taken with two different films and RVG, under standard conditions. The presence or absence of approximal caries was evaluated by six observers according to 3 points confidence scale. The actual status of each surface of the tooth was histologicaly determined from the teeth sections. Sensitivity and specificity of the imaging modalities were calculated and the observer responses were assessed with Fissure Exact Test. Results: The sensitivity values of Ekta speed plus, Insight and RVG were 24.3%, 18% and 46% respectively, while the specificity values were 86.4%, 87.1% and 78% respectively. The difference in detecting approximal carious lesions between the systems was not statistically significant.Conclusion: This study suggests that there is no significant difference between the three imagining modalities in detecting approximal caries. So, Insight film and RVG ui sensor merit considerations as the new standard of care. Key words: Dental Radiography, Digital Radiography, Caries Diagnosis