INTRODUCTION:The importance of early detection before the development of irreversible damage is now generally accepted. Most studies do not report the presence of non cavitated lesions, though they have been shown to have predictive value. OBJECTIVES: Validate LASER diode near-infrared transillumination (DIAGNOcam) as a diagnostic instrument in the early detection of noncavitated carious lesions. MATERIALS AND METHODS: Thirty three extracted sound premolars were examined on both approximal surfaces by (D1) EDX to determine Ca/P ions ratio (1.8≤), (D2) Periapical Digital Radiography, and (D3) LASER diode near-infrared transilluminated using DIAGNOcam. Any defect that indicated cavities by any of the mentioned methods discarded the tooth. To confirm that the selected sound teeth were intact, three teeth were randomly selected and invasively imaged by Scanning Electron Microscopy. The remaining thirty teeth were covered with acid resistant varnish except in 3x3mm in approximal areas and were immersed in a demineralizing solution for 72H Then, the teeth were then re-examined using D1, D2 & D3. To confirm that the results obtained, three teeth were randomly selected and invasively imaged by Scanning Electron Microscopy. RESULTS: D1 detected (100%) Ca/P ions ratio less than 1.8 (demineralized), D2 detected (6.67%) with enamel radiolucency and (93.33%) without any radiolucency, while D3 detected (100%) demineralized enamel. Pearson's Chi square test as well as validity tests showed that there is a statistically significant difference between D2 and the other diagnostic means (D1 and D3). SEM showed evidence of enamel demineralization in the three randomly selected teeth. CONCLUSIONS: LASER diode near-infrared transillumination (DIAGNOcam) is a reliable and valid method in detecting early enamel caries demineralization.