A 39-year-old male presented with fever for 3 days and arthralgia and backache. Examination found an ill-looking, anemic patient with lymphadenopathy and splenomegaly. Laboratory findings included severe neutropenia, anemia, thrombocytopenia, and elevated inflammatory markers. A bone marrow examination showed acute lymphoblastic leukemia (ALL) of the L2 subtype. The patient was diagnosed with febrile neutropenia secondary to ALL.