The highest case of malaria in East Nusa Tenggara Province is in Lembata Regency. The use of Artemisinin-based Combination Therapy (ACT) combined with Primaquine (PQ) in the treatment of vivax malaria aims to prevent treatment failure. The development of drug resistance and recurrence has been reported to have Plasmodium falciparum in several areas. For Plasmodium vivax, no resistance has been reported to the given regimen. Evaluation of the efficacy of Dihydroartemisinin piperaquine (DHP) combined with Primaquine (PQ) has never been done. Objective: To evaluate the efficacy and side effects of DHP + PQ in the treatment of Vivax malaria in the Wulandoni Sub-district, Lembata Regency. Methods: The subjects were vivax malaria patients who met the inclusion criteria as stated in the WHO anti-malarial drug resistance test. Clinical manifestations and side effects are monitored during the evaluation. Results: There were 52 respondents who followed the study to completion. The age of the patients involved ranged from 2 to 76 years consisting of toddlers, children, productive and elderly (≥ 46 years). From the Mann-Whitney test results, it was obtained p value <0.05 for groups of toddlers with productive age, toddlers with elderly, children with productive age and productive age with elderly. It was concluded that there were differences in parasite density among groups. Conclusion: There was a treatment failure as evidenced by blood tests with parasites still found in H3 because the patient did not take the medication completely. Clinical symptoms of vivax malaria patients were fever, chills and sweating accompanied by additional symptoms such as nausea, vomiting, diarrhea, headache, anorexia, aches and coughs. Side effects of DHP + PQ drugs were still in the mild category. Parasitological and clinical conditions and age had no relationship at all.