OBJECTIVES: Medication nonadherence among patients with chronic conditions is a significant barrier to achieving therapeutic outcomes. The objective of this study was to identify patient reported factors and reasons associated with medication nonadherence. METHODS: Online cross-sectional survey of patients taking medications for seven chronic conditions: asthma/COPD, bipolar depression, cardiovascular disease, diabetes, neuropathic pain, osteoporosis, and rheumatoid arthritis.  The first 50 patients to respond to the survey for each of the seven conditions were evaluated (total n=350). Patients provided demographic information and answered questions about their drug therapy including knowledge and satisfaction with their medications, difficulties in taking their medications, and how often they take their medication as prescribed.  Adherence was defined as patients self-reporting that they always take their medication as prescribed.  Nonadherence was defined as never, sometimes or often take medications as prescribed.  Multivariate logistic regression was performed to identify patient factors and reasons associated with nonadherence. RESULTS: Among the 350 patients who completed the survey, the average age was 54 years (standard deviation + 11 years, range 17-85 years) with the majority being female (78%), white (87%), having a some college education or more (73%) and having health insurance (87%). Approximately 58% of patients reported medication nonadherence.  No significant differences were observed between adherent and nonadherent patients with regard to age, sex, race, insurance status, condition, or number of medications taken.  Reasons significantly associated with nonadherence were forgetting, don’t like to take pills/give injection, cost of medication, symptoms improved so stopped taking medication, side effects too severe, and poor knowledgeable about their medications. CONCLUSIONS: Medication nonadherence is common and patient reported reasons for nonadherence include motivational factors, lack of understanding or knowledge, and treatment-related characteristics.  Interventions that motivate, educate and individualize drug therapy according to patients’ preferences and affordability may improve adherence.