ObjectiveTo assess general knowledge of diabetes and its determinants among adult men and women in a Japanese community.SettingA cross-sectional study with the residential registry in Gifu City. Blood tests were conducted to measure fasting blood glucose levels and the levels after 2 hours of a 75-gram oral glucose load. Participants’ previous diagnosis of diabetes and demographic status were identified from a questionnaire. A validated food frequency questionnaire was also administered. To assess the association between good knowledge of diabetes and the level of each factor, a logistic regression was utilised with adjustments for age, education and parental history of diabetes.ParticipantsA total of 1019 men and women aged 40–78 years.Primary outcome measureThe Diabetes Knowledge Questionnaire was administered. Participants with ≥75% of answers correct were defined as having a good knowledge of diabetes.ResultsPrevious diagnosis of diabetes was significantly associated with good knowledge of diabetes (OR=2.36; 95% CI 1.19 to 4.68). Among individuals with no previous diagnosis of diabetes, age ≥60 years (OR=0.55; 95% CI 0.36 to 0.86, p value for trend=0.02) and education <12 years (OR=0.54; 95% CI 0.30 to 0.97) were significantly associated with low knowledge of diabetes. The highest tertile intakes of green–yellow vegetables (OR=1.77; 95% CI 1.07 to 2.91, p value for trend=0.03) and seafood (OR=1.76; 95% CI 1.04 to 2.95, p value for trend=0.03) were associated with high knowledge of diabetes.ConclusionsSome diabetes risk factors were implied to determine the general knowledge of diabetes. Conducting further studies of knowledge in various populations is warranted.