Objective To investigate the incidence and clinical features of inflammatory bowel diseases (IBD) in Zhongshan City of Guangdong Province.Methods From July 2011 to June 2012,a prospective,population-based IBD epidemiological survey was conducted in Zhongshan City of Guangdong Province.All newly diagnosed IBD cases with Zhongshan census register were enrolled.The number of cases,Chinese age-standardized incidence and clinical features were analyzed.Results There were 48 new cases of IBD,of which 31 cases were ulcerative colitis (UC) and 17 cases were Crohn's disease (CD).The standardized incidence of IBD was 3.14/100 000,of which the incidence of UC was 2.05/100 000 and CD was 1.09/100 000.According to the Montreal classification,among 31 UC patients,11(35.5％) were proctitis,13 (41.9％) were left-sided colitis and seven (22.6％)were pancolitis.Among the 17 CD patients,lesions of four cases were terminal ileum type (one complicated with upper gastrointestinal bleeding),one case was colonic type and 12 cases were ileocolonic type (three cases complicated with upper gastrointestinal bleeding).Eleven cases were non-stricturing and non-penetrating type,four cases were stricturing type and two cases were penetrating type.Conclusions The incidence of UC is 2.05/100 000 and CD is 1.09/100 000 in Zhongshan City of Guangdong Province.Left-sided colitis is most common in UC and ileocolonic type is the most common in CD.