The results showed that 1.5% of Myanmar migrant workers were infected with malaria parasites. The Plasmodium spp. infections in this study were diagnosed by the detection of erythrocytic stages in blood films. The foreign workers randomly selected for a survey have resided in Thailand for more than six months so that these cases could not be defined as imported malaria infections. Likewise, the infecting species could not be actually identified because of the low parasitemia (mean = 144 parasites/L) and the finding of only few ring stages. However multidrug resistant falciparum malaria is common in Myanmar and Thailand; this indicated that malaria carriers should be concerned among foreign migrants in Thailand, particularly in Myanmar groups [1, 5, 8]. Similar to previous studies, the Plasmodium spp. infections predominated in males who are more attractive to mosquitoes than females and their hormone (testosterone) can act as anti- plasmodial immune repression . In spite of only 4 positive cases, the prevalence of malaria infections was not statistically significant different according to demographic characteristics including gender (P = 0.134), age (P = 0.793), and resident province (P = 0.661).