Background and AimColonic diverticulosis (CD) has been reported to be associated with presence of colon neoplasms (CNs) in Western patients, since most of the associated risk factors are common between them. However, such correlation has not been fully investigated in Asian patients. In this study, the association of CNs with CD was evaluated in a multicenter investigation.MethodsWe enrolled 5633 patients who underwent both colonoscopy and esophagogastroduodenoscopy due to annual follow‐up, screening for positive occult blood testing and abdominal symptoms between January 2016 and December 2017 at three institutions. The relationship between the presence of CNs and CD was investigated, and predictors for presence of CNs were determined by multivariate logistic analysis.ResultsThe enrolled patients consisted of 1799 (31.9%) with CD (average age 70.0 years, male 64.0%) and 3834 without CD (66.0 years, male 52.9%), with the prevalence of CNs in those groups 46.6% and 44.2%, respectively (P = 0.090). Predictors for early colon cancer were shown to be age (OR 1.02, 95% CI 1.01–1.04, P = 0.010), laxatives use (OR 1.76, 95% CI 1.17–2.64, P = 0.007), gastric neoplasms (OR 2.16, 95% CI 1.23–3.81, P = 0.008), and CD (OR 1.64, 95% CI 1.16–2.31, P = 0.005). Early colon cancer in the distal colon was most frequently detected in patients with right‐sided CD (RR 2.50, P = 0.001).ConclusionIn Japanese patients, early colon cancer was more frequently found in those with as compared to those without CD. The presence of CD may be an important indicator for an index colonoscopy examination to detect colon cancer. (Clinical‐trial‐registry: UMIN000038985).