OBJECTIVES: Medication adherence has been shown to be associated with the nature of the disease being treated and characteristics of the prescribed treatment. Non-adherence typically ranges between 30–50% of all patients. In addition, patients’ beliefs about health and illness and their behavioral expressions of their personality types may be important contributors to medication adherence. The objective of this study was to describe the associations between disease type, financial hardship and four personality temperaments (Traditionalists, Experiencers, Idealists, Conceptualizers) with self-reported medication adherence. METHODS:   Data were collected from the 2015 National Consumer Survey of the Medication Experience and Pharmacists’ Roles, via an on-line, self-administered survey coordinated by Qualtrics Panels in the United State of America, between April 28, 2015, and June 22, 2015. Data were analyzed using IMB/SPSS version 24.0 software. Logistic regression analysis and descriptive statistics were used. RESULTS: Out of 26,173 responses, 12,195 were taking at least one prescription medication and were not a licensed health professional, making them eligible for this study. Of these, the highest proportion of non-adherence among those without financial hardship was shown in breathing problems disease (37%), and least was in cancer (19%). Among those with financial hardship, non-adherence increased significantly (listed from the highest increase to lowest) to 41% for cancer, 40% for heart disease, 48% for diabetes, 45% for arthritis, 50% for obesity, and 44% for stroke. Of the four personality types, Experiencers had the highest rate of non-adherence and Traditionalists were the lowest in all disease types regardless of financial hardship. Logistic regression models showed that disease type, financial hardship, and personality type all affected the likelihood of non-adherence. CONCLUSIONS: In addition to acknowledging disease and treatment characteristics, financial hardship and personality type are important considerations for improving adherence to medications.