Background/Objectives: Acute lymphoblastic leukemia (ALL) is the most common childhood malignancy. Understanding its epidemiological characteristics is essential for guiding public health strategies. In this study, we characterized the epidemiological profiles that may contribute to the risk of ALL in children in southern Brazil. Methods: Clinical and epidemiological data from 71 children (1–15 years old) admitted and newly diagnosed with ALL at four hospitals in Curitiba, Paraná, Brazil, were retrieved and analyzed. Results: Among the 71 children with ALL, the majority were male (
n = 43, 60.6%), with an age range of 1–3 years (
n = 26, 36.6%), self-identified as White (
n = 47, 66.2%), and were born in Paraná state (
n = 61, 85.9%). Nearly half had a family history of cancer (
n = 33, 46.5%), primarily among grandparents (
n = 36, 61%). Parental environmental exposures included smoking (
n = 30, 42.3%) and occupational exposure to chemicals or radiation (
n = 17, 23.9%). At diagnosis, most patients (
n = 43, 60.5%) had a bone marrow blast count > 70%, and 27 patients (38%) had a peripheral blood blast count > 70%. B-cell ALL was the predominant subtype (
n = 61, 85.9%). In B-cell ALL cases, the most frequent molecular subtype was high hyperdiploidy (
n = 17, 23.9%). White blood cell counts differed significantly between the B-cell ALL and T-cell ALL groups (
p = 0.029). Conclusions: Our findings provide insights into ALL epidemiology in southern Brazil and highlight regional differences across the country.
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