GNU Health - GNU Health is a Free/Libre project for health practitioners, health institutions and governments.
Castor EDC - Castor offers you a user-friendly and fully featured application for electronic data collection.
Kareo - Kareo - Go Practice | Medical Office Software for Small Practices
OpenClinica - OpenClinica is an open source clinical trials software.
OpenMRS - OpenMRS is a community-developed, open source, enterprise electronic medical record system platform.
drchrono - An EHR built for your specialty: