Bile acids are important endocrine signalling molecules, modulating glucose homeostasis through activation of cell surface and nuclear receptors. Bile acid metabolism is altered in type 2 diabetes mellitus; however, whether this is of pathogenic consequence is not fully established. In this study urinary bile acid excretion in individuals with type 2 diabetes and matched healthy volunteers was assessed. Urinary bile acid excretion in type 2 diabetes patients was considered in the context of prevailing glycaemia and the patient body mass index. Urine bile acids were measured by liquid chromatography-tandem mass spectrometry, allowing individual quantification of 15 bile acid species. Urinary bile acid excretion in patients with type 2 diabetes who were normal weight (BMI 18.5-24.9 kg/m2) and overweight (BMI 25-29.9 kg/m2) were elevated compared to healthy normal weight volunteers, both p