Background: Anemia is one of the severe clinical outcomes associated with concomitantrninfection of malaria and soil-transmitted helminths. It affects growth, physical fitness, and rncognitive function, especially in children. The findings of previous studies done to assess therneffect of malaria soil- transmitted helminths co- infection on anemia showed some variation. Thisrnindicates the need for further studies in different populations. rnMethod An institutional-based cross-sectional study was conducted at three GovernmentalrnHealth Institutions, Arba Minch, and southern Ethiopia from November 2020- February 2021 on rna total of 321 malaria-positive study participants. Thick and thin blood films were prepared forrnmicroscopic examination of malaria parasites and identification of species. Malaria parasiterncount was done to determine the intensity of the infection. Stool wet mount was done to identify rnsoil-transmitted helminths. Kato-Katz was done for microscopic quantitative examination of soiltransmittedrnrnhelminths. Complete blood cell count was done to determine hemoglobin level and rnanemia prevalence. Socio-demographic data was collected using questionnaire. Data werernanalyzed using SPSS version 25. Independent samples t-test, one-way ANOVA, binary andrnmultivariate logistic regression analyses were done. rnResults; Anemia prevalence in this study was 38.3% and it was higher in the malaria withrnmultiple soil- transmitted helminth co- infection group (55.1%). Co-infection status (AOR=3.591, rnCI: 1.468 - 8.788, P=0.005), hookworm infection (AOR= 1.632, CI: 1.027-2.593, P=0.038), andrnits intensity, A.lumbricoides infection (AOR= 2.095, CI: 1.286-3.411, P=0.003), and its intensity rnwere significant predictors of anemia in this study. Malaria parasite density was significantly rnhigher in malaria with multiple STHs co-infected study participants F (2, 318) = 20.075. Itrnincreased with increasing intensity of hookworm, T.trichiura, and number of co- infecting rnhelminth species. But it decreased with increasing intensity of A.lumbricoides and S.mansoni. rnConclusion; this finding suggests that co- infection of multiple soil-transmitted helminth andrnmalaria are associated with anemia and low Hgb le vels, this indicates the importance of rnintegrated disease control interventions.