Health literacy (HL) is the ability to perform the basic reading, writing, and numerical skills required to function in a health care setting. Patients with adequate HL are able to read, interpret, and respond to health care information provided by health care providers and health plans. Several means of assessing HL are available for English- and Spanish-speaking patients. A review of the English-language literature on HL indicated that no prior studies included a subset of peritoneal dialysis (PD) patients. I administered the Rapid Estimate of Adult Literacy in Medicine (REALM) assessment tool to PD patients. I also asked patients for information about their highest education level completed. Following completion of the REALM, patients were classified as having adequate, marginal, or inadequate HL. As other studies have shown, patients with lower levels of education have inadequate HL. Patients with some college education or higher have adequate HL. However, at the average education level of patients, most patients have marginal HL. Relative lack of HL affects a patient's ability to make decisions regarding care as part of a home self-management program for end-stage renal disease (ESRD) and other chronic illnesses. Consequently, relative HL level affects the method of instruction and the time required for instruction during training of PD patients.