This study examines medication-related self-efficacy in a linguistically diverse group of patients with diabetes, hypertension, and elevated cholesterol. A telephone survey of 509 adults conducted in six languages (English, Spanish, Korean, Vietnamese, Mandarin, and Cantonese) was analyzed. Self-efficacy was assessed with the overall Medication Understanding and Use Self-Efficacy (MUSE) score and its two subscale scores on taking medication and learning about medications. Compared with English proficient (EP) patients, patients with limited English proficiency (LEP) had a lower mean learning self-efficacy subscale score (LEP: 14.5, EP: 15.4; p<.001) and no difference in the mean taking self-efficacy subscale score (LEP: 14.4, EP: 14.6; p=.40). Receiving verbal medication information (VMI) from providers modified the relationship between LEP status and learning self-efficacy. In conclusion, among patients with chronic illnesses, LEP patients had lower medication-related self-efficacy scores than EP patients, which may put them at greater risk for medication taking errors and lower adherence.