Treatment of Acute Lymphoblastic Leukemia is associated with neurocognitive deficits in young children. While computerized measures have been utilized in pediatric oncology research, they exclude patients below the age of 4 years old. Patients enrolled on “Treatment of Newly Diagnosed Acute Lymphoblastic Leukemia in Children and Adolescents” were offered participation in an optional cognitive study. Three-year old patients did not differ from four-year old patients on their ability to complete tests or perform tests. Including patients diagnosed at age 3 will serve to improve our understanding of at-risk patients and the cognitive trajectory of this age group both during treatment.