OBJECTIVES: Non-adherence to medications is a major problem among patients using chronic medications. Patients' medication beliefs are among modifiable factors considered to influence non-adherence. The primary aim of this study was to investigate associations between patients' beliefs about medications and non-adherence to chronic medications. METHODS: A cross-sectional self-administered survey was conducted of patients visiting a primary care clinic. Participants' medication beliefs and medication non-adherence were assessed using the Beliefs about Medications Questionnaire as developed by Horne et al. and the Morisky Medication Adherence Scale. Sociodemographic and clinical information also were collected. Spearman correlation analyses were used to assess associations between medication beliefs and medication non-adherence. RESULTS: A total of 443 patients were approached and 314 met study criteria of using at least one chronic medication for more than 2 months and ability to speak English. Of the 314 patients meeting inclusion criteria, 250 agreed to complete the survey, a response rate of 79.6%. Most of the participants (62.25%) were between 30 and 49 years old. Whites constituted 53% and blacks constituted 40% of the sample. Participants had a mean of 3.2 conditions (± 2.1) and used a mean of 5.3 medications (± 4.1). Participants perceiving less necessity to use medications (? = -0.2, p = 0.005) and with higher concerns about medications (? = 0.4, p <0.0001) had higher non-adherence to medications. Participants perceiving higher general harmful effects of medications (? = 0.3, p <0.0001) and with higher perceptions of over-prescribing of medications by physicians (? = 0.3, p <0.0001) had higher non-adherence to medications. Medication beliefs predicted 22% of variation in non-adherence to chronic medications. CONCLUSION: There were significant associations between medication beliefs and non-adherence. Health care providers may help patients improve their adherence to medications by resolving issues identified through medication beliefs assessment.