Hairy cell leukemia (HCL) is a rare chronic B-cell malignancy, a slow-growing leukemia that involves the bone marrow, spleen and peripheral blood with hairy cells. The complete blood count may reveal pancytopenia including neutropenia. Splenomegaly is a predominant feature while lymphadenopathy and hepatomegaly are rarely seen. Signs and symptoms of HCL include frequent infections, weakness or feeling tired. The treatment and prognosis of HCL depend on many risk factors such as gender, age, and it is very important to achieve CR which is a critical factor in the success and should be the treatment goal at each stage. Starting from 1984 until 2022 we have observed a total number of 76 patients (61 male, 15 female) with age ranging from 29-83 years, all with HCL. From the total number of patients, 71 (93.4%) were treated with chemotherapy with purine analogs ±, with splenectomy ±, INFα ±, different types of chemotherapy ±, monoclonal antibodies ±. The remaining 5 (6.57%) patients with HCL were only supportive and symptomatically treated. Out of the 71 patients, 50 patients (71.4%) were treated with purine analogs, the second group of 12 patients (16.9%) were treated with different approach without purine analogs, and the third group of 9 (12.7%) were treated with purine analogs and/or splenectomy, INFα, different types of chemotherapy and monoclonal antibodies. The most effective therapy for HCL has proven to be the usage of purine analogs for classical HCL, while for variants of the disease a combination of purine analogs and monoclonal antibodies.