Maintenance therapy is critical for successful treatment of pediatric acute lymphoblastic leukemia (ALL). Chemotherapy dosing during maintenance is guided by the absolute neutrophil count, and may be influenced by the rs2814478 polymorphism causing Duffy-associated neutrophil counts (DANC). Breast cancer patients with DANC experience more neutropenia and reduced treatment intensity, despite not having increased infections. To illustrate the potential impact in pediatric ALL, we describe maintenance therapy for a child with DANC. This case raises the possibility that maintenance therapy may be inappropriately reduced in patients with DANC when using conventional guidelines, potentially contributing to disparities in outcomes.