SurveyCTO - Collect data you can trust Offline or online, in the field, on the street, or in the lab.
Castor EDC - Castor offers you a user-friendly and fully featured application for electronic data collection.
CommCare - The digital platform for impactful frontline work everywhere
GNU Health - GNU Health is a Free/Libre project for health practitioners, health institutions and governments.
DHIS2 - Manage aggregate data with a flexible data model which has been field-tested for more than 15 years.
OpenClinica - OpenClinica is an open source clinical trials software.