OBJECTIVES: To determine factors associated with having one or more prescription drug fills (PDFs) in members of qualified health plans (QHPs). METHODS: This study used a large nationally representative administrative claims database supplemented with socioeconomic and community resource data.  The sample consisted of 1,823,677 members of QHPs who were enrolled for ≥10 months in 2014. Logistic regression was used to determine factors associated with having PDFs. RESULTS: A total of 1,230,981 (67.5%) members had ≥1 PDF during the study period. Living in a neighborhood with higher education levels (i.e., percent population with at least bachelor’s degree) was associated with higher likelihood of having PDFs (OR: 1.04-1.12; reference: 0-12%).  Lower median household income was associated with lower likelihood of having PDFs (OR: 0.73-0.90; reference $100,000+).  Members from neighborhoods with a higher proportion of non-white race/ethnicities were less likely to have PDFs (non-Hispanic black, OR=0.80; Hispanic, OR=0.95; Asian, OR=0.58).  Compared to Silver plan members, members of Gold plans were more likely to have PDFs (OR=1.07); but members of Platinum, Bronze, and Catastrophic plans were less likely to have PDFs (OR: 0.95, 0.65 and 0.83, respectively). Individual plan enrollment was associated with higher likelihood of having PDFs (OR=1.10), while on-exchange plan enrollment was associated with lower likelihood (OR=0.87).  Other factors associated with lower likelihood of having PDFs were being male (OR=0.62); younger age (OR: 0.55-0.71; reference: 31-65); and living in a non-metropolitan area (OR: 0.89-0.95).  CONCLUSIONS: This study provides evidence that the likelihood of having PDFs varies across member and plan characteristics, even after controlling for patient severity. Assuring appropriate treatment and adherence to medications for chronic conditions is inherent to achieving good health outcomes, thus it is important that QHPs identify and understand factors associated with lower likelihood of filling prescriptions in order to develop targeted interventions to achieve the most optimal outcomes in their members.