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Background: Rift Valley Fever (RVF) is a viral hemorrhagic fever that can be fatal to humans and livestock. During June-October 2018, reported RVF cases increased sharply in eight western and central Ugandan districts. We investigated to identify the scope of the outbreak, determine risk factors, and recommend control measures.Methods: We defined a probable case as acute onset of unexplained fever with thrombocytopenia or leukopenia, plus ≥1 of: unexplained bleeding, blurred vision, or unexplained death during June–October 2018 in a resident of the affected districts. A confirmed case was a probable case with a positive PCR test for RVF. We reviewed medical records and actively searched for cases in communities. In a case-control study, we compared exposures of cases and age-, sex-, and neighbourhood-matched controls. We reviewed livestock RVF surveillance data.Results: We identified 19 cases (17 confirmed, 2 probable); 13 (68%) died. The mean age of the case-patients was 36 (range: 27-55) years. The attack rate in men (15/10,000) was 19 times higher than in women (0.78/10,000). Stratified epidemic curves indicated multiple point-source outbreaks, often following skinning/butchering livestock or eating grilled meat from livestock that had been sick or died of unknown causes (‘sick/dead livestock’). All case-patients with data (n=18) ate or butchered meat from sick/dead livestock. Of the 18 case-patients and 90 controls who participated in the case-control study, 10 case-patients (56%) and five controls (5.6%) cut or handled raw meat from sick/dead livestock (ORadj=14, 95%CI=2.8-72). RVF-seropositive livestock were identified from serum samples taken from farms where human cases had occurred.Conclusion. Human RVF outbreaks in Western and Central Uganda in 2018 were caused by contact with raw meat of sick/dead livestock. We recommended wearing protective gear during butchering, and safe handling and disposal of carcasses of sick/dead livestock. RVF surveillance data between human and livestock health sectors should be shared to facilitate early warning and detection for RVF.