Prostatitis is a highly prevalent nosologic entity and hence has an enormous financial impact on health systems as well as negative repercussions on patients' quality of life. The symptoms are ambiguous, diagnostic methods are controversial and treatments are long and produce inconsistent results; consequently, although not life-threatening, prostatitis has become one of those diseases that is difficult both for the patient and for the physician who attempts to help, sometimes without success. Although an infectious etiology is accepted in most cases, there are major controversies about both the diagnostic methods used and their interpretation. Recently the National Institutes of Health in the USA has proposed a new classification of this disease to substitute that used for the last twenty years. This new classification may provide a more effective approach to the diagnosis and treatment of this insidious disease.