OBJECTIVE: Acute lymphoblastic leukaemia (ALL) is the most frequent childhood cancer. Infant ALL (<
1 year) is rare, but it captures a lot of interest due to its poor prognosis, especially in patients harbouring METHODS: Original articles, letters, or conference abstracts published up to June 2022 were identified using the PubMed, Web of Science, and Embase databases, and 33 observational studies were selected. RESULTS: The study reveals several well-established associations across the literature, such as maternal exposure to pesticides and high birth weight, and outlines suggestive associations, such as parental heavy smoking, parental use of several medications (e.g., dipyrone), and maternal exposure to air pollution during pregnancy. CONCLUSIONS: This scoping review summarizes the few observational studies that have analysed the prenatal and perinatal risk factors for ALL in infants diagnosed before the age of 1 year. The results of this review highlight the lack of research into this specific age group, which merits further research.