The Volunteer Collaborator Networks (VCNs) of Latin America are one of the oldest and most successful examples of community participation in malaria control. They are made up of unpaid community volunteers, known as Volunteer Collaborators, who are selected by their neighbors and are trained and supervised by a member of the National Malaria Service (NMS). When a febrile patient visits the home of a Volunteer Collaborator, the volunteer worker takes a thick blood smear, completes a patient report form, and administers a presumptive treatment for malaria. The blood smear is examined in an NMS laboratory, and if malaria parasites are found, a radical or curative treatment is forwarded to the Volunteer Collaborator so that it can be administered to the patient. There is no charge for either the blood smear or the antimalarial medication. The VCN of Guatemala was established in 1958. Currently, more than 5,000 Volunteer Collaborator posts are operating throughout the malarious areas of the country. The volunteers range in age from 12 to 76 years old and 61% are men. Approximately 15% have no formal education, and only 27% have a sixth grade or higher education. The median length of service is 35 months (range three months to 26 years); 33% have worked for five or more years. Male Volunteer Collaborators had significantly lower turnover rates than females, as did married Volunteer Collaborators when compared with single volunteers. An inverse relationship was noted between the amount of education a Volunteer Collaborator had and his length of service. With modifications tailored to meet the objectives of a malaria control program and the local epidemiologic setting, the VCN can serve as an excellent model for community participation in malaria case detection and treatment in other regions of the world. In particular, in areas where the primary goal of the malaria program is to prevent mortality and morbidity through the provision of readily accessible, appropriate drug therapy, VCNs are an attractive alternative to self-medication and an effective adjunct to treatment of malaria at health posts which are often located at a considerable distance from the patient's village. Experience gained with this system can be valuable in developing approaches to community involvement in other efforts to improve the health of villagers in developing countries.