Abstract: OBJECTIVE To explore the epidemiological and clinical characteristics of the patients with Brucella bloodstream infections so as to provide bases for scientific diagnosis and treatment of brucellosis. METHODS The clinical data were retrospectively collected from the patients with Brucella bloodstream infections who were treated in The First Hospital of Shanxi Medical University from Oct. 2022 to Oct. 2024. The patients were divided into the young group(age between 16 and 44 years old), the middle-aged group(aged between 45 and 59 years old) and the elderly group(aged no less than 60 years old). The epidemiological characteristics, clinical manifestations and result of clinical laboratory test were observed and compared among the three groups of patients. RESULTS A total of 65 patients were enrolled in the study, with the young group 18 cases, the middle-age group 27 cases, the elderly group 20 cases. The epidemiological data indicated that there was significant difference in the history of contact among the three groups of patients(P=0.022). The cliical manifestations were dominated by fever (93.85%) and fatigue(47.69%); there were significant difference in the indicence rates of fatigue, low back pain, muscle pain, joint pain and spondylitis among the three groups(P= 0.027, 0.033, 0.024, 0.028, 0.008). Ther result of clinical laboratory testing showed that there were significant differences in the levels of alkaline phosphatase and albumin among the three groups of patients(P=0.041,0.019). The patients with decresed percentage of eosinophils accounted for 86.15%, the patients with decreased level of albumin 95.38%. CONCLUSIONS The incidence rates of fatigue, low back pain, muscle pain, joint pain and spondylitis are higher among the middle-age and elderly patients with Brucella bloodstream infections than among the young patients. There are significant differences in the results of clinical laboratory tests for alkaline phosphatase and albumin, it is suggested that the clinicians should carry out the early prevention and treatment based on the clinical characteristics of the different age groups of patients.