Background: In this retrospective analysis, we investigate the clinical features and prognosis of 23 infant patients (< 1 year of age) diagnosed with acute lymphoblastic leukemia (ALL). Methods: We used clinical data of 23 children diagnosed with infant ALL at the Department of Pediatric Hematology & Oncology, Wuhan Children’s Hospital, between 1st January 2014 and 30th September 2019. EFS and OS rate curves were computed using the Kaplan-Meier estimator. The impact of prognostic factors on outcome was analyzed using the Cox model. Results: The median WBC was 46.14 (6.46–513) × 109/L at initial diagnosis. All 21 patients immunophenotyped by flow cytometry had B-lineage ALL. KMT2A-rearrangement was identified in 72.2% （13/18）patients. Mutation screening for 13 patients indicated 4 patients with KRAS mutations, 4 with TTN mutations, 2 with NOTCH1 mutations, 2 with PTPN11 mutations and 2 with NRAS mutations. Of 12 patients who received chemotherapy, complete remission was achieved for 83.3% patients after one course of remission induction. A total of 3 patients underwent related haploidentical allogeneic hematopoietic stem cell transplantation. The expected 2-year overall survival (OS) rate was 55.6 ± 15.2% and the expected event free survival rate (EFS) was 44.4 ± 15.7%. Univariate analysis revealed WBC > 100 × 109/L at initial diagnosis as a risk factor for poor OS and EFS. Conclusion: Treatment of infant ALL with the standard childhood ALL regimen achieved an OS rate similar to patients with high-risk ALL, and WBC at initial diagnosis may be an important prognostic indicator.