Objectives. We present a case report of a patient with malaise, abdominal pain, and vomiting, later underwent bone marrow biopsy and found to have CNL with no genetic mutation. Case presentation. A 40 years old male came into hospital with malaise, abdominal pain, nausea, and vomiting. Furthermore there were bilateral lymphadenopathy in the neck, hepatomegaly and moderate splenomegaly in abdominal examination. Anemia, leukocytosis and increase of Lactat Dehydrogenase (LDH) were found. Bone marrow aspiration and biopsy was performed and showed predominant neutrophil and the bone marrow biopsy showed hypercellular bone marrow with increased myeloid-neutrophil, increased myeloid erythroid ratio. Outcome. After further investigation this patient was diagnosed with chronic neutrophilic leukemia based on bone marrow aspiration and biopsy result. © 2023, Amaltea Medical Publishing House. All rights reserved.