Background: Brucellosis is one of the most common infectious diseases in Iran with very different clinical manifestations.

Methods: In this retrospective descriptive study, all patients with brucellosis, who were admitted in Farshchian Hospital in Hamadan, Iran in 2005 to 2010, were enrolled in the study. The data were collected from the patients' medical records and were entered in forms for analysis.

Results: A total of 230 patients with brucellosis, including 130 (56.5%) male and 100 (43.5%) female patients with a mean age of 40.84±20.29 years, who mostly (72.2%) lived in rural areas were enrolled in the study. Outbreaks were most common in spring and summer and the main route of transmission was consumption of contaminated dairy products (60.3%). The most common symptoms were fever (77.4%), arthralgia (70%), sweating (47%), malaise and fatigue (46.5%). Arthritis and epididymo- orchitis were seen in 121 (52.9%) and 48 (8.20%) patients, respectively. CBC analysis showed leukocytosis in 20.8% of the participants. ESR rise was noted in 59.5% of the patients and 52.9% had positive CRP.

Conclusion: Given to various clinical presentations, brucellosis should be considered in the differential diagnosis of individuals with chronic fever with or without other organ abnormalities.