Recently the Department of Health (DOH) instituted a change in the national antimalarial drug guidelines changing from using chloroquine (CQ) and sulfadoxine pyrimethamine (SP) monotherapy as first and second line drugs, respectively, to a combined chloroquine plus sulfadoxine-pyrimethamine as first-line treatment, and artemether-lumefantrine (Coartem) as second line treatment. This change was made due to increasing levels of drug resistance to the previous first and second-line therapies. In order to have an improved understanding of the trends of antimalarial drug resistance in the Philippines, the DOH is initiating a sentinel surveillance system for monitoring of antimalarial drug resistance. Three sites have been selected to be representative of the country.