Low health literacy is associated with higher mortality, higher rates of hospitalization, and poor self-management skills for chronic disease. Early, unplanned hospital reutilization after discharge is a common and costly occurrence in U.S. hospitals. Still, few studies have examined the relation between health literacy and 30-day hospital reutilization rates. The authors examined the association between health literacy and 30-day reutilization of hospital services (readmission or return to the emergency department) in an urban safety net hospital, and conducted a secondary analysis of data from the control arm subjects of the Project RED and the RED-LIT trials. Health literacy was measured using the REALM tool. The primary outcome was rate of 30-day reutilization. The authors used multivariate Poisson regression analysis to control for potential confounding. Of the 703 subjects, 20% had low health literacy, 29% had marginal health literacy, and 51% had adequate health literacy. Sixty-two percent of subjects had a 12th-grade education or less. Subjects with low health literacy were more likely to be insured by Medicaid (p < .001); Black non-Hispanic (p < .001); unemployed, disabled, or retired (p < .001); low income (p < .001); and less educated (high school education or less, p < .001). The fully adjusted incidence rate ratio for low health literacy compared with adequate health literacy was 1.46 (CI [1.04, 2.05]). Low health literacy is a significant, independent, and modifiable risk factor for 30-day hospital reutilization after discharge. Interventions designed to reduce early, unplanned, hospital utilization after discharge should include activities to mitigate the effect of patients' low health literacy.