Background: Radiologic diagnostic methods for internal resorption include conventional periapical radiography (PA radiography), Complementary metal Oxide Semiconductor imaging (CMOS), Photostimulable phosphor (PSP) imaging and Cone beam Computed Tomography (CBCT). This study aims to examine the sensitivity and specificity of CBCT, PSP, CCD, and PA Radiography for early diagnosis of internal resorption. Material & methods: 72 single-rooted premolars were divided into three intervention groups and a control group. The teeth were split mesiodistally into two parts. Cavities of 0.3 mm depth were created on the buccal half of the root in middle one third in Group A. In Group B cavities of 0.4 mm, Group C cavities of 0.6 mm and in control Group D no cavities were created. Finally, the teeth fragments were fused using glue, fixed in sockets of one human dry mandible and were examined with the four different procedures. Results: The sensitivity of the four imaging procedures for diagnosis of internal root resorption of 0.3 mm was 100%, 60%, 73%, and 53% respectively. However, the sensitivity of all four procedures for diagnosis of internal root resorption with 0.4mm and 0.6 mm in depth was the same and equal to 100%. The specificity of the four procedures for diagnosis of internal root resorption of any depth was100%, 83%, 100%, and 75% respectively. Conclusion: CBCT provides the most accurate information on the depth and location of root resorption followed by the CMOS and PSP respectively. Conventional intraoral periapical radiography was the least accurate procedure.