The isolated spleen involvement is a rare presentation of Langerhans cell histiocytosis (LCH) and can lead to a misdiagnosis. We report a case of LCH in an infant presentated isolated splenomegaly and prolonged fever. A 1-month-old girl admitted due to pe-techiae, presented with fever for a week and splenomegaly, and showed marginal im-provement on empirical treatment. The fever and progressive spleen enlargement per-sisted over 4 weeks and the cause remained unclear, even after thorough evaluation including bone marrow aspiration and biopsy. LCH was confirmed by splenectomy, and involvement of other organs was excluded. Splenectomy is valuable in the diagnosis of LCH presented with isolated splenomegaly without other organ involvement which may show more aggressive clinical course, but it should be limited to absolutely neces-sary indications.