Community health workers (CHWs) are increasingly being required to perform complex health care activities, especially in community cardiovascular disease and stroke prevention. However, currently, there are no psychometrically validated instruments for assessing CHW competencies in these roles. This article describes the development and validation of the stroke literacy assessment test (SLAT)--pertaining to the Life's Simple Seven (LS7) risk factors for stroke--for evaluating CHWs' competencies in the context of education and training programs. The SLAT was developed using an iterative instrument design protocol, followed by empirically testing the instrument in 68 CHWs from the Columbia University Institute for Training Outreach and Community Health (InTOuCH) in New York. Data collection began in March 2021 and continued through May 2021. The evaluation was based on four types of validity evidence: (a) content validation with expert reviews of items and overall domain, (b) validation on examinee response processes with cognitive interviews, (c) item validation and diagnostic analysis, and (d) validity evidence based on expected directional group differences. In addition, the internal consistency reliability of the total test scores, with the best functioning items, were evaluated. Two such iterative cycles yielded a 34-item, written structured response test that assesses the "factual knowledge" and "application" levels of cognition, and demonstrates sufficient validity and reliability (Cronbach's [alpha] = 0.69) for use with CHWs specializing in stroke prevention efforts. The SLAT is a novel, valid, and reliable instrument that contributes to filling a critical gap in rigorous competency assessments for CHWs deployed in chronic disease prevention.