AIM: To investigate the incidence and localizations of lymphoid follicles (LFs) in early colorectal neoplasms in human beings.METHODS: From July 1992 to September 1999, a total of 1 324 early colorectal neoplasms were removed endoscopically or surgically at our hospital; 1 031 (77.9%)were available for analysis in this study. Localization of LFs was defined histologically: as submucosal LFs, if located under the muscularis mucosa; and as intramucosal LFs, if located across or oyer the muscularis mucosa.RESULTS: Histologically, the materials included 903intramucosal neoplasms and 128 submucosal cancers.Overall incidence of LFs was 27.2% (280/1 031). The incidence of LFs was significantly higher in females (33.6% vs 24.9%,P=0.0064), the right-sided colon (32.2% vs 25.6%, P=0.0403) and in flat or depressed type lesions (34.6% vs 25.2%, P＜0.0001)as compared to males, left-sided colon and protruding type lesions, respectively. The incidences of intramucosal neoplasms and submucosal cancers were 24.3% and 43.8%, respectively (P＜0.0001). Localizations of LFs (intramucosal LF/submucosal LF) in depressed, flat,and protruding types were 1/24, 14/36, and 131/74,respectively.CONCLUSION: The incidence of LFs in early human colorectal neoplasms significantly differs by gender,location, macroscopic type, and histology. Moreover,localization significantly differs by macroscopic type.