Financial support was provided by Conselho Nacional de Desenvolvimento Cient??fico e Tecnologico (CNPq, Brazil) Universidade Federal do Rio Grande do Sul. Departamento de Gen?tica. Porto Alegre, RS, Brazil. Universidade Federal do Rio Grande do Sul. Departamento de Gen?tica. Porto Alegre, RS, Brazil. Universidade Federal do Para. Laborat?rio de Microbiologia e Imunologia. Bel?m, PA, Brazil. Minist?rio da Sa?de. Secretaria de Vigil?ncia em Sa?de. Instituto Evandro Chagas. Programa de Ensaios Cl?nicos em Mal?ria. Ananindeua, PA, Brasil. Minist?rio da Sa?de. Secretaria de Vigil?ncia em Sa?de. Instituto Evandro Chagas. Programa de Ensaios Cl?nicos em Mal?ria. Ananindeua, PA, Brasil. Universidade Federal do Par?. Laborat?rio de Gen?tica Humana e M?dica. Bel?m, PA, Brazil. Universidade Federal do Par?. Laborat?rio de Gen?tica Humana e M?dica. Bel?m, PA, Brazil. Hospital de Cl?nicas de Porto Alegre. Unidade de Bioestat?stica. Grupo de Pesquisa e P?s Gradua??o. Porto Alegre, RS, Brazil. Universidade Federal do Rio Grande do Sul. Departamento de Gen?tica. Porto Alegre, RS, Brazil. Aim: The association of transporters gene polymorphisms with chloroquine/primaquine malaria treatment response was investigated in a Brazilian population. Patients & methods: Totally, 164 Plasmodium vivax malaria infected patients were included. Generalized estimating equations were performed to determine gene influences on parasitemia and/or gametocytemia clearance over treatment time. Results: Significant interaction between SLCO2B1 genotypes and treatment over time for parasitemia clearance rate on day 2 were observed (p FDR = 0.002). SLCO1A2 and SLCO1B1 gene treatment over time interactions were associated with gametocytemia clearance rate (p FDR = 0.018 and p FDR = 0.024). ABCB1, ABCC4 and SLCO1B3 were not associated with treatment response. Conclusion: The present work presents the first pharmacogenetic report of an association between chloroquine/primaquine responses with OATP transporters.