Louisiana is severely affected by HIV/AIDS, ranking fifth in AIDS rates in the USA. The Louisiana Public Health Information Exchange (LaPHIE) is a novel, secure bi-directional public health information exchange, linking statewide public health surveillance data with electronic medical record data. LaPHIE alerts medical providers when individuals with HIV/AIDS who have not received HIV care for >12 months are seen at any ambulatory or inpatient facility in an integrated delivery network. Between 2/1/2009 and 1/31/2011, 488 alerts identified 345 HIV positive patients. Of those identified, 82% had at least one CD4 or HIV viral load test over the study follow-up period. LaPHIE is an innovative use of health information exchange based on surveillance data and real time clinical messaging, facilitating rapid provider notification of those in need of treatment. LaPHIE successfully reduces critical missed opportunities to intervene with individuals not in care, leveraging information historically collected solely for public health purposes, not health care delivery, to improve public health.