A total of 18,845 blood samples were tested by the Acridine Orange (AO) quantitative buffy coat (QBC) method, under white light and UV light and compared with thick blood films, for the detection of malarial parasites. The positivity rate was 25% by the AO-QBC technique and was 18% by the thick film technique. The increased sensitivity, combined with the rapidity and simplicity of the AO-QBC technique, establishes its superiority over the conventional thick film method, in the sentinel surveillance of malaria, in endemic areas. The comparative unit price of the AO-QBC test and conventional microscopy is Rs. 38.00 and Rs. 14.00 respectively. But, the ancillary advantages of the AO-QBC method over the conventional method more than offset the cost difference.