Objective: This in-vivo study was performed to assess the interrater agreement and reliability of ICDAS (visual), transillumination, radiographic, and laser fluorescence proximal caries detection tools in between primary and adjacently erupted permanent molars. Method and Materials: This study was in accordance with Guidelines for Reporting Reliability and Agreement Studies. Two calibrated examiners assessed the nonobvious noncavitated apparently sound 100 interproximal sites using predefined criteria. Interrater agreement was analyzed as proportion of agreement. Interrater reliability assessment was performed using weighted kappa statistics and intraclass correlation coefficient. Results: The maximum interrater agreement was projected with conventional bitewing radiography (97%), and the minimum with DIAGNOdent pen (84%), with significant difference (P .001) in the proportion of agreement. All methods showed substantial interrater reliability, except fiber-optic transillumination. Maximum interrater reliability was noticed for ICDAS (International Caries Detection and Assessment System) method with a weighted kappa value of 0.80 (96% CI, 0.58 - 0.93) followed by conventional and digital bitewing radiography, with values of 0.74 (95% CI, 0.51 - 0.96) and 0.73 (95% CI, 0.43 - 0.92) respectively. Conclusion: ICDAS and bitewing radiography seem to be the most reliable methods, with a higher proportion of agreement between the examiners compared to the other methods addressed in this study for proximal caries detection. Keywords: caries, diagnosis, interrater agreement, interrater reliability, permanent dentition, primary teeth