Objective:To investigate malaria prevalence and socio-economic conditions in East Timor. Methods: Blood samples were collected from 650 individuals distributed among six districts in East Timor. 434 and 216 individuals were sampled by passive and active case detection, respectively (PCD, ACD).Results: The results showed that the plasmodium infection prevalence was 18.9% with predominance ofPlasmodium falciparum(P. falciparum) infections (60.2%). The majority of cases were detected in children between 2-14 years old in both PCD and ACD. Participants residing in Same and Lospalos were at a higher risk of malaria. The percentage of infections associated to the lack of bed net use was twice as high as users (25.2% vs 12.5%). The prevalence of malaria among participants who lived in brick/cement houses (8.3%) was two times less than those who lived in other types of houses (3.7%). There was a significantly lower prevalence of infection detected in individuals living in complete housing constructions with absence of domestic animals in or near the houses.Conclusions:The major risk factors for malaria in East Timor are age, lack of bed net use, incomplete housing constructions and exposure to mosquitoes.