The indirect hemagglutination antibody (IHA) test for melioidosis was evaluated in 373 healthy blood donors, 65 cord blood samples from healthy neonates, 30 patients with acute melioidosis (13 of whom were septicemic), and 154 individuals hospitalized with various illnesses. Twenty-one percent of healthy blood donors had titers ≥ 1: 40, demonstrating that Songkla is an endemic area. The sensitivity, specificity, and accuracy at titers ≥ 1:160 were 77%, 92% and 89%, respectively. This cut-off level is higher than that used in previous reports from non-endemic areas. The test did not recognize patients with the acute fulminating form.