OBJECTIVES: Patient non-adherence to medications is associated with poorer health status; yet, intentional (e.g., purposefully skipping doses) and unintentional (e.g., forgetting) non-adherence can reflect distinct patient characteristics.  This study investigates the burden of intentional (INA) or unintentional (UNA) non-adherence among eleven costly chronic conditions. METHODS: EU 2010 National Health and Wellness Survey data were used, including 19,279 (of 57,805) respondents who reported taking prescription medication for any of these conditions: asthma, pain, congestive heart failure (CHF), COPD, diabetes, hypertension, depression, bipolar disorder, peripheral vascular disease (PVD), transient ischemic attack (TIA), and stroke.  Morisky Medication Adherence Scale items were summed to create INA (“stop taking medicine when feeling better” and “…when feeling worse”) and UNA (“forget to take medicine” and “careless about taking medicine”) scores ranging from 0=adherence (reference) to 1=moderate and 2=high non-adherence.  Generalized linear models predicted health utilities (scored from the SF-12v2) from INA or UNA, controlling for sociodemographic characteristics and comorbidities.  RESULTS: Among those taking medication for asthma (n=3147), pain (n=6605), CHF (n=248), COPD (n=584), diabetes (n=3062), hypertension (n=8821), depression (n=3714), bipolar disorder (n=240), PVD (n=106), TIA (n=287), or stroke (n=356), 49.7% were male, mean age was 52.9 years (SD=15.0), and 32.3% and 30.8% exhibited some INA and UNA, respectively (rINA/UNA=0.34, p<0.001).  Across conditions, adjusting for covariates, high (b=-0.040) and moderate (b=-0.028) INA was associated with lower health utilities, as was high UNA (b=-0.017), all p<0.001.  This pattern was significant for high non-adherence in diabetes (INA: b=-0.058; UNA: b=-0.023) and hypertension (INA: b=-0.054; UNA: b=-0.032), p<0.01; it was on average non-significantly negative within other conditions, but significantly positive in pain and PVD. CONCLUSIONS:   These results suggest INA may have a stronger negative impact on health status than UNA, which can help guide adherence-improving intervention strategies.  The results also highlight disease areas in which interventions may yield better outcomes.