AimsTo investigate the association of high life satisfaction with incident Type 2 diabetes separately in men and women. MethodsA longitudinal analysis was conducted among the 7107 participants (3664 men, 51.5%; 3443 women, 48.5%) aged 25-74 years (mean sd age 47.8 13.7 years) of two population-based MONICA/KORA surveys conducted in 1989-1995 and followed up until 2009. Life satisfaction was assessed using a one-item instrument with a six-order response level, which was dichotomized into high vs medium or low. Sex-specific hazard ratios were estimated using Cox proportional hazards models. ResultsCrude incidence rates for Type 2 diabetes per 10 000 person-years were lower in participants with high than in those with medium or low life satisfaction (men: 57 vs 73; women: 37 vs 48). In men with high life satisfaction, there was a 27% risk reduction in incident Type 2 diabetes (hazard ratio 0.73, 95% CI 0.56-0.94; P=0.02) in a model adjusted for sociodemographic, behavioural and clinical risk factors. The association lost statistical significance after further adjusting for depressed mood (hazard ratio 0.79, 95% CI 0.61-1.03). Life satisfaction was not significantly associated with incident Type 2 diabetes in women. ConclusionLife satisfaction may be a valuable asset in assessing risk of Type 2 diabetes, especially in men, and in the development of more effective prevention strategies to deter onset of diabetes. More research is needed to investigate the underlying potential causal pathways that may link life satisfaction to the development of Type 2 diabetes.