The immunology of the prostate has recently developed into a new field of research in urology. Although we do not yet understand why the leukocyte population increases, we know that most resected prostate tissue shows signs of an inflammatory reaction. Different types of inflammation exist, and must be distinguished carefully according to distribution and location of leukocytes and histology of the surrounding tissue. This article reviews recent findings and discusses the complex mechanisms involved in the prostatic inflammatory response. The roles of estrogen, interleukin (IL)-6, IL-8, IL-15, and IL-17 are examined.