Malaysian Ministry of Health guidelines currently recommend chloroquine and primaquine as first line treatment for the erythrocytic and hypnozoite life stages of uncomplicated P. vivax malaria respectively. While resistance to chloroquine has previously been documented in Sabah [35] and Peninsular Malaysia [36-38], the unstable transmission dynamics and recent reduction in P. vivax incidence due to public health measures mean the current risk of chloroquine-resistant P.vivax transmission is likely to be low. Despite this, due to increasing resistance in surrounding countries including Indonesia, Thailand, Vietnam, and PNG [39], transient populations of migrant workers, and recent concerns of the failing efficacy of hypnozoite eradication by primaquine [40], the need for ongoing therapeutic efficacy monitoring is recommended [41].