Is there any evidence that e-health-using information technology to manage patient care-can have a positive impact in developing countries? Our systematic review of evaluations of e-health implementations in developing countries found that systems that improve communication between institutions, assist in ordering and managing medications, and help monitor and detect patients who might abandon care show promise. Evaluations of personal digital assistants and mobile devices convincingly demonstrate that such devices can be very effective in improving data collection time and quality. Donors and funders should require and sponsor outside evaluations to ensure that future e-health investments are well-targeted.