Objective: Because health literacy is related to healthcare outcomes, this study looked at reading and comprehension levels in a sample of urban, low-income persons. Design: This was a descriptive exploration of reading comprehension levels, controlled for medical problems that could impact on vision and therefore ability to read. Setting: Ninety persons were recruited in the waiting areas of a healthcare provider serving the homeless and urban poor. Method: Visual acuity and blood pressures were obtained and for diabetic patients measures of glycaemic control were recorded. Reading and comprehension was tested with the Wide Range Achievement Test (WRAT) 4 standardized assessment. Limited demographic data was obtained. Descriptive and frequency statistics were calculated as well as Pearson "r" coefficients. Results: Results indicated that most participants were healthy or had well controlled conditions. No health parameters were significantly related to reading/comprehension scores. Reading and comprehension scores were lower than standardized norms with mean reading just under grade 10 and comprehension at mid-ninth grade. The mean composite scores placed them in the lower 30th percentile of readers. Women scored below men in all areas. Conclusion: Participants in this study had reading and comprehension levels at beginning high school level. They may have difficulty understanding healthcare hand-outs and instructions. Healthcare information sources should be written at levels comprehensible to clients, and alternative methods of information dissemination should be considered. (Contains 1 table, 2 figures, and 1 note.)