Context Health literacy affects a patient's ability to navigate through the system of care for late-stage kidney disease, including evaluation, waiting, and recovering from kidney transplant. Objectives To develop and provide a preliminary evaluation of a knowledge and decision-making capacity tool, which is a component of health literacy. Design Cross-sectional design with purposive sampling. Setting Vascular access, dialysis, and outpatient transplant clinics. Methods A Decision-Making Capacity Assessment Tool (DMCAT) was developed and administered to 127 adults at different stages in the kidney care process. Results The DMCAT tool is positively and significantly correlated to the other 2 previously validated instruments and accounts for more variance than the other 2 tools in the regression models. We found significant differences in patients' health literacy and decision-making capacity related to their stage of care. Decision-making capacity appeared to be an important component of health literacy and should be considered as health care providers tailor care to meet patients' needs.