ImportanceA prompt malaria diagnosis is crucial for the management of children with febrile illness in sub-Saharan African countries, where malaria remains a leading cause of mortality among children younger than 5 years of age. The development and distribution of point-of-care rapid diagnostic tests (RDTs) for malaria has transformed practice, but limited systematic evidence exists on how malaria RDTs have affected the management of febrile illness and mortality for children younger than 5 years of age across sub-Saharan Africa countries.ObjectiveTo evaluate the association between the distribution of malaria RDTs and the management of febrile illness and mortality among children younger than 5 years of age in sub-Saharan African countries.Design, Setting, and ParticipantsThis quasi-experimental study used a novel dataset linking malaria RDT distribution to 165 nationally representative household surveys across 35 sub-Saharan African countries with mortality data. The sample comprised approximately 3.9 million child-year observations and approximately 260 000 febrile illness episodes in children younger than 5 years of age between 2000 and 2019.Main Outcomes and MeasuresFixed-effects linear probability models were used to analyze the association between variation in malaria RDTs distributed per child younger than 5 years of age (by country per year) and blood testing, antimalarial drug use, antibiotic use, use of symptomatic treatments, and mortality rates. Variation in the effects of testing and treatment was also assessed across the sub-Saharan African countries that had varying prevalence of malaria.ResultsThe mortality sample included 1 317 866 children and the fever sample included 256 292 children. The mean age of the children with febrile illness was 2.4 years (SD, 1.3 years) and 49% were female. Each additional malaria RDT distributed per child younger than 5 years of age was associated with an increase of 3.5 percentage points (95% CI, 3.2-3.8 percentage points) in blood testing, an increase of 1.5 percentage points (95% CI, 1.2-1.8 percentage points) in the use of antimalarial drugs, an increase of 0.4 percentage points (95% CI, 0.1-0.6 percentage points) in antibiotic use, and a decrease of 0.4 percentage points (95% CI, 0.1-0.8 percentage points) in the use of treatments for symptoms. Each additional malaria RDT distributed per child younger than 5 years of age was associated with a reduction in child mortality of 0.34 deaths per 1000 child-years (95% CI, 0.15-0.52 deaths per 1000 child-years). The effects of malaria RDT distribution on medication use and child mortality varied across prevalence settings (low vs high) for malaria; there were survival improvements only in areas that had a high prevalence of malaria.Conclusions and RelevanceIncreasing distribution of malaria RDTs was associated with increased blood testing, increased use of antimalarial drugs, and modestly improved survival in children younger than 5 years of age in sub-Saharan African countries. However, malaria RDTs were associated with increases in the rates of antibiotic use that were already high, suggesting that more comprehensive approaches to case management of febrile illness are needed.