Malaria is the most significant parasite disease in humans. It is transmitted to humans by the bite of earned female mosquitoes. Despite the fact that malaria is a preventable and curable disease, it is still a public health concern. It is most widespread in tropical and subtropical areas of Africa and Asia. The largest number of imported malaria patients in Croatia are domestic and foreign seafarers, rarely tourists and workers who resided in malarial areas. The diagnosis is made on the basis of a positive finding of the parasite in the blood. About 30,000 sailors sail in Croatia, about 10,000 of which are on foreign ships. On average, 8 males get sick every year from malaria. Given that many seafarers are sailing under the flags of other countries, there is no reliable data on the number of malaria seafarers, but the number is assumed to be much higher. The causes of imported malaria are mainly due to the non-implementation or insufficient implementation of chemoprophylaxis, ie malaria medicines taken before departure, during and after returning from a trip.