Objective To evaluate the diagnostic efficacy of narrow band imaging (NBI) international colorectal endoscopic (NICE) classification in distinguishing neoplastic from non-neoplastic colorectal polyps during routine clinical practice. Methods A total of 224 lesions detected by white light colonoscopy by non-expert endoscopists were collected in this retrospective study. Each lesion was assessed by NBI and classified by NICE classification. The results were compared with pathological findings from endoscopic or surgical resected specimen. Results Among these 224 polyps, there were 59 cases of type 1, 159 of type 2 and 6 of type 3 according to NICE classification. There were 58 non-tumorous and 166 tumorous polyps according to pathological diagnosis. The total diagnostic sensitivity, specificity, positive predictive value, negative predictive value and accuracy of NICE classification for colorectal tumor were 91.6%, 77.6%, 92.1%，76.2% and 87.9%, respectively. Diagnostic sensitivity and accuracy in big (more than 10 mm in diameter), small (6 to 9 mm in diameter) and mini (less than 5 mm in diameter) polyp groups were 100.0% and 95.7%, 97.0% and 87.8%, 80.9% and 83.3%, respectively. Diagnostic accuracy showed a decreasing tendency in accord with polyp size, without significant difference between the three groups (P=0.694). Conclusion NICE classification with non-magnified NBI is effective in distinguishing neoplastic and non-neoplastic colorectal polyps by non-expert endoscopists and is potentially worth popularizing for routine clinical practice.