Brucellosis is a zoonosis caused by several species of Brucella. Brucellosis is usually an acute or sub-acute febrile illness that histologically develops granulomatous inflammation. Brucella prostatitis is a very rare complication and is usually accompanied by epididymo-orchitis. We now report a case of histologically proven granulomatous prostatitis due to Brucella without clinical evidence of epididymo-orchitis. A 61-year-old farmer presented with myalgia, low back pain, and fever. A needle biopsy of the prostate was performed due to symptoms of urinary frequency and high prostate specific antigen levels (17.3 ng/mL). Histologically, the prostate showed granulomatous inflammation without caseous necrosis. Polymerase chain reaction (PCR) studies of blood and prostatic tissue for Brucella were positive, while a PCR study for Mycobacterium tuberculosis was negative. The patient was treated with doxycycline and rifampin. A possibility of Brucella prostatitis should be considered in the differential diagnosis of granulomatous prostatitis or prostatitis of unknown origin associated with or without epididymo-orchitis.