A malaria control effort in Nicaragua involving the mass, short-term distribution of anti-malaria medicines to a target population of all citizens above one year of age is detailed. About 70% of the population received anti-malarials in November, 1981 and 8 million packets of chloroquine and primaquine were distributed by 70,000 health campaign workers and their assistants. Training and mobilization efforts used volunteers from local community organizations. Mass public education was a key focus in the weeks before drug administration. The effects of the campaign were immediately apparent with a rapid decline in incidence after drug administration. Ongoing community environmental control, case finding, and health education activities continued to improve the malaria situation post-campaign. Further, the campaign promoted the decentralization of malaria control activities and integration of the malaria efforts with the nationwide primary health care system.