Brucellosis is a systemic bacterial disease with an acute or insidious onset, characterized by continued, intermittent, or irregular fever of variable duration, headache, weakness, sweating, chills, arthralgia, depression, weight loss, and generalized aching. It is predominantly an occupational disease among those working with infected animals or their tissues, especially farm workers, veterinarians, and abattoir workers. Brucellosis has been an emerging disease since the discovery of Brucella melitensis by Bruce in 1887. Worldwide, brucellosis remains a major source of disease in humans and domesticated animals. Although the reported incidence and prevalence of the disease vary widely from country to country, bovine brucellosis caused mainly by B. abortus is still the most widespread form, also occurring in Korea. The vaccination for Brucella was first done on cows in 1998. After inoculation, Brucella developed in a group of cows. And then the first human case occurred in 2002, followed by 16 cases in 2003 by B. abortus. Prevention of brucellosis in humans still depends on the eradication or control of the disease in animal hosts, hygienic precautions to limit the exposure to infection through occupational activities, and effective heating of dairy products or other potentially contaminated foods. Physicians and veterinarians should be concerned about specific environments and clinical patterns of brucellosis. They should make efforts to recognize, evaluate, and control brucellosis.