Cases of induced malaria have been notified in S. Paulo State, Brazil, in recent years. At the same time the number of cases imported from endemic regions of Brazil has been increasing. One case of induced malaria by Plasmodium vivax was registered in Presidente Prudente, located in the west of the State, in 1988 and a further eleven cases in 1989. This city is considered to be one of the main transit ports for people who come into the State from the Amazonian region. The patients declared that they had not been to any possible transmission area of malaria. All of them had, however, taken cocaine, sharing the same contaminated needle and syringe. Previously, one person with imported malaria was detected, who had transmitted the disease to the first case in 1988 and also to a further group of 3 people in 1989. One of these three latter cases then transmitted the disease to two other people. As the group of people continued to use the drug among themselves, 2 new cases arose. Afterwards, they re-infected themselves again (one of the was re-infected twice). The test for Human Immunodeficiency Virus was positive for 5 individuals, of whom one had a negative result and 2 others did not undergo the test. This information is discussed within the present context.