OBJECTIVES: The impact of Type 2 diabetes mellitus (T2DM) on health related quality of life (HRQL) is complex due to the burden of disease, lifelong treatment requirements and comorbidities. This study aimed to capture UK societal utility values for health states associated with T2DM and treatment-related adverse events (AEs) to assess the burden of the disease and common AEs. METHODS: Nine health state descriptions were developed (from a literature review and patient and clinician qualitative input) depicting the burden associated with T2DM and treatment related AEs.  These were mild/moderate urinary tract infection (UTI); severe UTI; mycotic infection; moderate hypoglycaemic events; severe hypoglycaemic events; fear of hypoglycaemia; gastrointestinal symptoms; and hypovolaemic events.  Members of the UK general public (n=100) valued these states using the time trade-off (TTO) methodology to elicit utility values (between 0= dead, 1= full health).  Regression analysis was conducted to understand influence of age and gender. RESULTS: All treatment-related AEs were found to have a significant effect on utility.  From the T2DM baseline state (0.92), the experience of AEs was associated with the following disutility: T2DM with hypovolaemic events (0.08); T2DM with mild/ moderate UTIs (0.09); T2DM with moderate hypoglycaemic events (0.11); T2DM with severe hypoglycaemic events (0.15); T2DM with fear of hypoglycaemia (0.15); T2DM with severe UTIs (0.19); T2DM with GI symptoms (0.24); andT2DM with mycotic infection (0.25); Males consistently scored the states with significantly lower utility values, but no significant age effects emerged. CONCLUSIONS: Findings suggest that adverse events in T2DM can be a burden for some individuals. The study indicates the potential importance of including information regarding AEs in economic evaluations.  Although some states were rated severely in terms of utility, in reality, many of these only last a few days, therefore having a minimal quality adjusted life year (QALY) impact.