Study purpose was to revise and examine the validity of the Medication Adherence Self-Efficacy Scale (MASES) in an independent sample of 168 hypertensive African Americans: mean age 54 years (SD = 12.36); 86% female; 76% high school education or greater. Participants provided demographic information; completed the MASES, self-report and electronic measures of medication adherence at baseline and three months. Confirmatory (CFA), exploratory (EFA) factor analyses, and classical test theory (CTT) analyses suggested that MASES is unidimensional and internally reliable. Item response theory (IRT) analyses led to a revised 13-item version of the scale: MASES-R. EFA, CTT, and IRT results provide a foundation of support for MASES-R reliability and validity for African Americans with hypertension. Research examining MASES-R psychometric properties in other ethnic groups will improve generalizability of findings and utility of the scale across groups. The MASES-R is brief, quick to administer, and can capture useful data on adherence self-efficacy.