Chronic prostatitis is a common condition, with an incidence estimated at between 9%-14% of men worldwide. It is a medically controversial condition with significant attendant morbidity. According to a recent consensus report from the National Institutes of Health (NIH), chronic prostatitis patients fall into one of three categories: chronic bacterial prostatitis (category II prostatitis); chronic pelvic pain syndrome (category III prostatitis); or asymptomatic inflammation (category IV prostatitis). Prostatic tissues are best penetrated by drugs with a high pKa and high lipid solubility, such as quinolones, macrolides, tetracyclines, and sulfa drugs. Ciprofloxacin has been shown to be effective in the treatment of chronic bacterial prostatitis caused by Escherichia coli. The older quinolones demonstrate superiority against chronic bacterial prostatitis caused by gram-negative pathogens; the newer quinolones may be more effective against gram-positive pathogens and anaerobes. Despite continuing controversy, antimicrobial agents are the most common therapy employed in the treatment of chronic prostatitis. While some patients with nonbacterial (category III) prostatitis do improve with antibiotics, prolonged courses in the absence of documented infection or symptomatic improvement are not warranted. Prospective, randomized, placebo-controlled trials will hopefully lead to a clearer understanding of the role of antimicrobial agents in chronic bacterial prostatitis within the next year.