Objectives: To determine if the excess mortality associated with Bipolar disorder (BD) is independent of lifestyle. Methods: Prospective study of a community-representative sample of 12,203 men aged 65–85 years followed for 17.7 years. We used the 8-item ‘prudence score’ to assesses lifestyle behaviours, including the use of alcohol and smoking, physical activity, body mass and key aspects of diet. Scores of 5 or more indicate a prudent lifestyle. Results: 69 (0.6%) men had BD–a larger proportion of them than the remainder of the sample had diabetes, ischaemic heart disease, stroke, chronic respiratory diseases and dementia. The odds of a prudent lifestyle were 40% lower among participants with BD. BD was associated with increased risk of future contact with health services due to ischaemic heart disease and cancer, and respiratory, digestive and renal diseases, although such risk became comparable to that of men without BD for men with BD and a prudent lifestyle. The adjusted mortality hazard associated with the diagnosis of BD was 1.66 (95%CI = 1.20, 2.28), while the mortality hazard associated with a prudent lifestyle was 0.81 (95%CI = 0.78, 0.85). The mortality hazard for men with BD who were also prudent was 0.83 (95%CI = 0.52, 1.30). All analyses were adjusted for sociodemographic measures and prevalent morbidities. Conclusion: The excess morbidity and mortality of older men with BD seems to be mediated by non-prudent lifestyle practices. If future studies can demonstrate that this association is causal, then lifestyle interventions will need to become an integral part of the management of older adults with BD.