Malaria (caused primarily by Plasmodium falciparum) is endemic in the southern third of Burkina Faso, occurring seasonally between June to November, with most cases occurring between August and October. In Burkina Faso there has been no evidence of a recent decline in malaria incidence as seen in some other African countries. Although the policy is to treat uncomplicated malaria with artemisin combinations, in practice chloroquine remains the treatment used in most health facilities. Several studies have shown that seasonal IPT in children (IPTc) can provide a high degree of protection against clinical malaria. SP+AQ is the most effective regimen but amodiaquine is not well tolerated and resistance to SP is increasing n many areas. Alternative regimens are required. Piperaquine (PQ), a long acting antimalarial used for prophylaxis in China, is suitable for use for IPT. In studies in Senegal and The Gambia piperaquine plus SP or dihydroartemisinin (DHA) was as effective and better tolerated than SP+AQ. The purpose of this study is to determine whether DHA-PQ is more effective than SP+AQ in preventing spread of drug resistant parasite genotypes and to determine the pharmacokinetics of piperaquine in children who receive this drug for IPT. Little was known about the pharmacokinetics of piperaquine until recently, and there is currently only limited information about the pharmacokinetics of piperaquine in children. The pharmacokinetic data from this study will allow us to estimate the optimum dose regimen for piperaquine; the current recommended regimen for DHA-PQ is three doses over three days. For IPT, a single dose regimen is highly desirable as it would be easier to deliver and better accepted by communities.