BACKGROUND: Accurate endoscopic diagnosis is crucial for determining the appropriate treatment strategy for colorectal lesions, which may include cold snare polypectomy, endoscopic mucosal resection, or endoscopic submucosal dissection. SUMMARY: While white light imaging (WLI) serves as the basic and initial method for endoscopic diagnosis, additional techniques such as narrow band imaging (NBI), blue laser/light imaging (BLI), and magnified observation of pit patterns are necessary when WLI results are inconclusive. These advanced diagnostic methods enable precise differentiation of lesions such as adenoma, T1 cancer, and sessile serrated lesion. Furthermore, recent advancements in endoscopic systems have enhanced image clarity and detail, thereby improving diagnostic accuracy. KEY MESSAGES: This review provides an in-depth discussion on how magnified endoscopy, utilizing the Japan NBI Expert Team (JNET) classification with NBI/BLI and pit pattern classification with chromoendoscopy, aids in the accurate diagnosis of colorectal lesions.