A rapid, immunochromatographic test for malaria diagnosis, 'Determine(TM) malaria pf', was evaluated by a field team in the epidemic-affected, forest setting of Chhindwara district, in Madhya Pradesh, central India. In all, 526 fever cases were screened for Plasmodium falciparum in October or November, 1999. Those found to be infected were treated with sulfadoxine-pyrimethamine and primaquine. Using microscopy as the gold standard, the new test had a sensitivity of 98% and a specificity of 87%. The positive and negative predictive values were 88% and 98%, respectively. Although follow-up of 64 subjects on day 7 post-treatment revealed that 20% of those who then appeared smear-negative were still antigenaemic, 34% of the subjects were still smear-positive, for asexual parasites, at that rime. The Determine test was found to be very easy to perform and the results could be read reliably by field workers, without any supervision. The ease of use of the test indicates that it could be useful in the management of malaria, particularly in remote and inaccessible areas, provided that its accuracy can be assured and that it can be made affordable.