Background:rnMalaria is still among the major diseases of public health importance in Ethiopia. Ethiopia presentsrna diversified ecological situation, resulting in a highly variable eco-epidemiology of malaria.rnFollowing the scale-up of antimalarial interventions in the past two decades, malaria burden hasrnsignificantly declined leading to the National Malaria Control Program (NMCP) in Ethiopia to reembarkrnonrnrna strategy for step by step nationwide malaria elimination. Learning from the failedrnmalaria elimination endeavors of the 1960s, achieving such an ambitious target, given therncomplicated eco-epidemiology of malaria in Ethiopia may require several inputs and evidences. rnrnMeasures of malaria burden and transmission dynamics using conventional diagnostic methodsrn[microscopy and Rapid Diagnostic tests (RDTs)] may be incomplete, particularly, in low andrnseasonal transmission settings, where few infections are detected. Unlike most parts of Africa, P.rnfalciparum and P. vivax co-exist in Ethiopia. Malaria elimination requires determining the actualrnburden, distribution as well as detection and cleaning of all forms of malaria infection. Thernknowledge gap in the occurrence, prevalence and distribution of Glucose-6-PhosphaternDehydrogenase (G6PD) deficiency has been a limiting factor for radical cure of relapsing malariarnand transmission interruption. The group of drugs within 8-aminoquinolines, such as Primaquinernand Tafenaquine, are the only available treatment of relapsing malaria. Eight-aminoquinolines canrninduce severe hemolysis in G6PD deficient individuals. The study used advanced tools torninvestigate the epidemiological risk factors relevant for malaria elimination.rnrnObjective: rnThis study used serology and molecular methods to describe the malaria (Plasmodium spp) burdenrnand distribution, as well as to determine G6PD deficiency prevalence and allelic types, in order tornproduce reliable evidence for malaria elimination in Ethiopia. rnrnMethodology:rn Dried blood spot (DBS) samples collected in 2011 and 2015 as part of the national householdrnMalaria Indicator Surveys (MIS) were used. The Ethiopian Malaria Indicator Surveys (EMISs) utilized a multi-stage cross sectional surveys representating the various malaria epidemiologicalrnsettings in Ethiopia. EMIS-2015 samples were investigated using bead-based multiplex assays forrnIgG antibodies for six Plasmodium spp antigens: four human malaria species-specific merozoiternsurface protein 1 19kD antigens (MSP-1) and apical membrane antigen 1 (AMA-1) for P.rnfalciparum and P. vivax. Seroprevalence was estimated by age group, elevation, and administrativernregions. Seroconversion rates were estimated using a reversible catalytic model fitted withrnmaximum likelihood method. Sub samples of EMIS-2015 from three administrative regionsrn(Amhara, Tigray and Benishangul Gumuz regions) were screened by Microscopy, RDTs andrnnested Polymerase Chain Reaction (nPCR) for malaria parasites and results were compared torndetermine prevalence of subpatent infections. A randomly selected subset of samples from EMIS2011rnrnwere genotyped by polymerase chain reaction-restriction fragment length polymorphismrn(PCR-RFLP) technique and three common G6PD genotype variants: G6PD*A (A376G),rnG6PD*A- (G202A) and Mediterranean (C563T) were investigated. rnrnData were analysed using Stata 13 (College Station, USA). Serology data were generated from arnmultiplex instrument as Mean Floruescent Intensity minus background (MFI-bg). To dichotomizernseropositivity, log-transformed MFI-bg values were fitted to a two-component Finite MixturernModel (FMM) by the FMM procedure with normal distribution and maximum likelihoodrnestimation outputs. A seropositivity cutoff value was determined by the mean MFI-bg value of thernfirst (assumed seronegative) component plus three standard deviations. Plasmodium falciparumrnand P. vivax seropositivity were defined as being positive for either or both MSP-1 and AMA-1rnantigens. Species specific MSP-1 antigens were used for P. malariae and P. ovale seropositivity.rnrn EMISs sampling weights were used to ensure the representativeness of the samples tested to thernstudy population. Adjustments were made by region, elevation, and age group. Linear and multiplernlogistic regression models with 95% confidence intervals (CI) were employed to determine thernassociation of risk factors with Plasmodium spp infection. Differences in distributions werernevaluated using Chi square (Ï‡2) test with P value < 0.05 considered significant. Spatial analysisrnand geographical mapping were done using QGIS and ArcGIS softwares.rnrn Main Findings:rnNational seroprevalence for antibodies to P. falciparum was 32.1% (95% CI: 29.8-34.4) and 25.0%rn(95% CI: 22.7-27.3) for P. vivax. Estimated seroprevalence for P. malariae and P. ovale werern8.6% (95% CI: 7.6-9.7) and 3.1% (95% CI: 2.5-3.8), respectively. Seroprevalence estimates werernsignificantly higher at lower elevations (