OBJECTIVES: Approximately 64% of US type 2 diabetes (T2DM) patients are in poor glycaemic control. Previous studies show that a high proportion of patients in poor glycaemic control also have poor treatment adherence. The aim of this analysis was to investigate the characteristics and proportion of patients with T2DM treated with insulin that engage in non-adherent behaviour, and to assess if there is an association between non-adherent behaviour and HbA1c. METHODS:  Data from the National Health and Wellness Survey (NHWS) from 2012-2013 was applied. The NHWS is an annual health questionnaire administered to a nationwide sample of adults in the US. All T2DM insulin users with non-missing HbA1c data were included (N=2,288). The eight-item Morisky Medication Adherence Scale (MMAS-8) was used to assess the level of non-adherent behavior. Bi-and multivariate analyses were conducted to determine the association of a) the MMAS-8 score and individual items with demographic and health history factors and b) HbA1c when controlling for these factors. RESULTS:  Among T2DM insulin users, 39.29% and 19.97% reported medium and low adherence to insulin treatment. Commonly reported non-adherent behaviours included: having difficulties remembering (33.87%), feeling hassled (30.33%) and forgetting medication (21.59%). Patients with poorer adherence were younger, had diagnosed and initiated insulin more recently, were more likely to be female, of low socioeconomic standing and to have diabetic complications (p< 0.05). In terms of HbA1c, levels were at 7.12% among those with high adherence and significantly higher at 7.31% and 7.81% among those with medium and low adherence respectively (p<0.05). Adherent behaviour which was strongly associated with HbA1c included skipping medication, forgetting medication when traveling, forgetting medication and feeling hassled about the medication regimen (p< 0.05). CONCLUSIONS: Non-adherent behaviour seems associated with poorer HbA1c possibly due to skipping and forgetting doses. Less stringent treatment regimens may increase adherence and therefore improve glucose control.