A seroepidemiological survey of HTLV-1 infection in Guangdong Province was reported. 2224 serum samples from various populations were collected and antibodies to HTLV-1 in sera were detected with indirect immunofluorescent assay. Total seropositive rate was 1.57% (35/2224). The antibody positive rates of HTLV-1 in sera from healthy individuals (n = 1810), blood donors (n = 248), patients with T cell leukemia (n = 109) and patients with neurological diseases (n = 57) were 1.27%, 0.40 %, 7.30% and 5.26% respectively. There was a significant difference between the patients with T cell leukemia and the healthy individuals (P<0.005).