['Iron overload predisposes to diabetes and higher ferritin levels have been associated with diabetes. However, it is unclear whether ferritin reflects differences in iron-related parameters between diabetic and nondiabetic persons. We examined associations of serum ferritin, iron and transferrin saturation with Type 2 diabetes in adults without genetic predisposition to iron overload.', 'Cross-sectional analysis of community-dwelling men and women aged 17-97\xa0years from the Busselton Health Survey, Western Australia. Men and women carrying genotypes associated with haemochromatosis (C282Y/C282Y or C282Y/H63D) were excluded. Serum ferritin, iron and transferrin saturation were assayed.', 'There were 1834 men (122 with diabetes, 6·6%) and 2351 women (141 with diabetes, 6%). In men, higher serum ferritin was associated with diabetes after adjusting for age, smoking, alcohol, cardiovascular history, body mass index (BMI), waist, blood pressure, lipids, C-reactive protein (CRP), adiponectin, alanine transaminase (ALT) and gamma-glutamyl transpeptidase (GGT) [odds ratio (OR): 1·29 per 1\xa0unit increase log ferritin, 95% confidence interval (CI)\xa0=\xa01·01-1·65, P\xa0=\xa00·043]. In women, higher serum ferritin was associated with diabetes [fully adjusted OR: 1·31 per 1\xa0unit increase log ferritin, 95% CI\xa0=\xa01·04-1·63, P\xa0=\xa00·020; 1·84 for tertile (T) 3 vs T1, 95% CI\xa0=\xa01·09-3·11]. Neither iron levels nor transferrin saturation were associated with diabetes risk in men or women. Higher ferritin was not associated with insulin resistance in nondiabetic adults.'] Are higher ferritin levels , but not serum iron or transferrin saturation , associated with Type 2 diabetes mellitus in adult men and women free of genetic haemochromatosis?