Hairy cell leukemia (HCL) is a rare chronic B-cell lymphoproliferative disorder characterized by splenomegaly without lymphadenopathy, pancytopenia, and bone marrow infiltration by an atypical cell with circumferential prominent hairy cytoplasmic projections. A high index of suspicion in such situation (splenomegaly with few atypical lymphoid cells) made us to go for bone marrow examination that revealed characteristics morphological findings of hairy cell leukemia (HCL) with increased reticulin framework. The diagnosis was confirmed when flow cytometery demonstrated positivity for hairy cell markers like CD11c,CD103 , FMC-7  and negativity for splenic lymphoma with villous lymphocytes ( SLVL) markers like CD19,CD25.  Accurate diagnosis of this entity and its differentiation from   other lymphoproliferative disorders is essential because of therapeutic and prognostic consideration.