BACKGROUND: Patients diagnosed with prostate cancer are often counseled about treatment options with the use of terms that are part of the "core vocabulary" of prostate cancer. It is hypothesized that predominantly lower literacy patients would demonstrate a severe lack of comprehension of prostate cancer terms, thus validating the findings of a previous single-institution study. METHODS: A previously developed survey was used to evaluate understanding of terms related to urinary, bowel, and sexual function. The survey was administered by trained evaluators at 2 safety net clinics that provide care for low-income, predominantly African American patients. Comprehension was assessed using semiqualitative methods coded by 2 independent investigators. Literacy and numeracy were also evaluated. RESULTS: Among 109 patients who completed the study, only 5% understood the function of the prostate, and 15%, 29%, and 32% understood the terms "incontinence," "urinary function," and "bowel habits," respectively. Lower levels of comprehension were observed for compound words, such as "vaginal intercourse" (58%), versus single words such as "intercourse" (95%), validating previous work. Median school level was 13 years, yet median literacy level was only ninth grade, and reading level was significantly correlated with comprehension. Only 30% of patients correctly calculated both a fraction and a percent. CONCLUSIONS: Lack of comprehension of prostate health terminology is pronounced in this patient population and may be widespread. This lack of comprehension potentially limits the ability of patients to participate in informed decision-making. These results validate the findings of previous studies and support a continued need for refined methods of prostate cancer education. Cancer 2013;119:3204-11.