Background Septicemia is an important cause of treatment-related mortality and treatment failure in pediatric acute lymphoblastic leukemia (ALL) in developing countries. A multicenter CCCG-ALL-2015 study was conducted in China and factors associated with septicemia and mortality were studied. Methods Patients participated in CCCG-ALL-2015 study from January 2015 to December 2017 were included. Patients with documented septicemia were identified from the Data Center and additional data were collected. Results A total of 4080 patients were recruited in the study and 527 patients with septicemia were identified (12.9%, 95% CI 11.9%-13.9%). The intermediate risk (IR)/high risk (HR) group had significantly higher incidence of septicemia as compared with low risk (LR) group, 17.1% vs 9.1% (OR 2.07, 95% CI 1.71-2.49, P < .001). Induction phase was the period with majority of septicemia episodes happened, 66.8% in LR and 56.1% in IR/HR groups. Gram-positive bacteria accounted for 54.1%, gram-negative bacteria 44.5%, and fungus 1.4% of positive cultures. Multidrug-resistant organisms were detected in 20.5% of all organisms. The mortality rate after septicemia was 3.4% (95% CI 1.9%-4.9%). Multiple logistic regression identified female gender, comorbid complications, and fungal infection as risk factors associated with mortality. Gram-negative septicemia was associated with higher mortality, 4.9% vs 1.4% (OR 0.28, 95% CI 0.09-0.88, P = .02). There was marked variation in the incidence of septicemia among the 18 centers, from 4.8% to 29.1%. Conclusion Overall the incidence and pattern of septicemia in this multicenter study in China was similar to the reports of western countries. The septicemia-related mortality rate was low. There was marked variation in the incidence of septicemia among the centers.