The objective of this study was to detect antibodies for human T lymphotropic virus (HTLV) in subjects residing in two communities located in the eastern Brazilian Amazon and on the shores of the Tucuruí hydroelectric power plant. A total of 657 serum samples were analysed using an enzyme-linked immunosorbent assay with an anti-HTLV antibody (Symbiosis™, São Paulo, Brazil), demonstrating a virus prevalence of 4.7%. Most individuals with HTLV were aged over 30 years (P = 0.013), were unmarried (P = 0.019), resided in the area for more than 10 years (P = 0.001), had a low level of education (P = 0.015), and had a family income of up to $305 (100%). In contrast, there was no significant association between infection and sex, city of birth, haemotransfusion, or previous surgery. The prevalence observed in these communities suggests that the residents should be concerned about HTLV infection, and that some areas may become endemic for HTLV. J. Med. Virol. 85:1585–1590, 2013. © 2013 Wiley Periodicals, Inc.