OBJECTIVES.: To evaluate the variation of hematological profiles of patients infected with uncomplicated Plasmodium vivax (Pv) and P. falciparum (Pf) malaria before, during and after treatment in a population of the Loreto region. MATERIALS AND METHODS.: This study was conducted between 2010 and 2012, in Zungarococha (Iquitos). The 425 participants had three visits (visit 1-day 0-before treatment, visit 2-day 7-during treatment, visit 3-day 28-after treatment), complete blood count, microscopic and molecular diagnosis (PCR). RESULTS.: At the first visit, 93 (21.9%) participants were found positive for Pv and 34 (8.0%) for Pf. All positives showed a reduction in hematocrit, white blood cell count (WBC), ablated and segmented neutrophils, eosinophils and platelets (p<0.001) compared to the negative group. A higher percentage of ablated neutrophils was found in Pf and segmented neutrophils in Pv compared to the negative group. Variations in hematological profiles were observed after treatment for both species; ablated neutrophils decreased, platelets increased, eosinophils increased at day 7 and declined at day 28, hematocrit and segmented neutrophils decreased at day 7 and normalized at day 28. Interspecies differences over time showed a bigger daily decrease in ablated neutrophils in Pv-infected when compared to Pf. CONCLUSIONS.: The hematological profile in uncomplicated malaria-positive patients varies over time during and after treatment. These are indicators of disease progression and help in the therapeutic surveillance of Plasmodium-infected patients.