Background: Patient organizations are gaining increasing social and political importance throughout Latin America and the Caribbean (LA&C). However, there is still limited information on the characteristics of and coordination among these organizations. In response to this lack of information, the Pan American Health Organization (PAHO), the Institute of Clinical and Sanitary Effectiveness (IECS), and Pacientes Online have launched a collaborative project to identify these organizations and their main characteristics. Objectives: Create a patient organization database in LA&C. Methods: We performed a search on patient organizations in LA&C between March and September 2007. The main sources of information used were the following: generic search engines on Internet (Google and similar); registries at official agencies and independent research institutes; key informants at patient associations and organizations. Upon contact with key informants, the snow ball technique was used to identify new patient organizations. Data collection proceeded through a semi-structured questionnaire completed by patient organizations either through direct contact (E-mail, telephone) or online. The data collected focused on the following main areas: contact information and general infrastructure; mission and vision; activities, target populations, geographical scope, and health conditions addressed. The health conditions were independently coded by two researchers using the ICPC-2. Results: We identified more than 250 organizations in 22 countries. The organizations were founded between 1921 and 2007. The main health conditions addressed were HIV/AIDS, cancer (especially breast cancer), disability, Alzheimer’s disease, and alcoholism. Argentina was the country in which most societies were identified, followed by Costa Rica and Chile. The main target populations of these organizations were the general public, children, and women. Most organizations carried out activities at the national level and confirmed status as legal entities. Conclusions: Patient organizations are spread throughout LA, whereas the identification of organizations in the Caribbean has been more difficult. The scope of the patient organizations is highly verticalized, as they tend to focus on specific health conditions. Their classification in freely accessible databases would facilitate the formation of new patient networks. More research is necessary in order to identify more associations, their level of institutional coordination, and their success factors.