Introduction: Autoimmune hemolytic anemia (AIHA) is a rare autoimmune disease caused by the production of autoantibodies against the self-antigenic parts of erythrocyte membranes, thus shortening their life span and causing normo-/makrocytic anemia. Aim: The aim of this study was to examine the clinical and laboratory characteristics of newly diagnosed adult patients diagnosed and treated at the Clinical Hospital Centre Osijek. Materials and Methods: This cross-sectional study was performed using medical records at the Department of Haematology at the Clinical Hospital Centre Osijek combined with demographic and clinical characteristics and initial laboratory findings of adult patients with newly diagnosed AIHA in the period from the 1st of December 2018 to the 30th of November 2020. Results: Thirteen patients with newly diagnosed autoimmune hemolytic anemia were included, 7 out of 13 were female (53,8 %) and 5 out of 13 (46,2 %) were male patients. The median value of the age at diagnosis of AIHA was 65 years old (range from 34 to 89 years). AIHA was classified as primary in 4 (30,8 %) patients, while in other cases (9 patients, 69,2 %) appeared as the secondary, which is associated with various underlying conditions: most commonly with B-lymphoproliferative neoplasms (4 patients, 44,4 % secondary), other autoimmune diseases (2 patients, 22,2 % secondary) and infectious diseases (2 patients, 22,2 % secondary). Most patients had warm antibody hemolytic anemia (11 patients, 84,6 %), cold antibody hemolytic anemia had only one patient (7,7 %) and mixed antibody hemolytic anemia also had only one patient (7,7 %). The median hemoglobin concentration at the diagnosis of AIHA was 66 g/l (32 – 84 g/l), while lactate dehydrogenase was 611 U/l (373 – 1035 U/l). Conclusion: Overall, we conclude that most patients had warm antibody hemolytic anemia and a secondary form of the disease, most commonly associated with malignant diseases (lymphoproliferative neoplasms).