This paper shows that replacing paper-based records with electronic medical records (EMRs) improves HIV patient retention and prevents AIDS deaths in the low-income country of Malawi. An event study of 106 HIV clinics shows a 28 percent reduction in annual deaths five years after EMR implementation, with the greatest impact on children. Improvements in health outcomes appear due to efficiency gains, rather than to changes in the medical care provided at visits. These efficiency gains allow clinics to better manage patient data, trace lapsed patients and return them into care, and adapt to higher patient volumes over time.