Prostatitis is characterized by voiding symptoms and genitourinary pain and is sometimes associated with sexual dysfunction. Up to 25% of men receive a diagnosis of prostatitis in their lifetime, but <10% have a proven bacterial infection. The causes and treatment of nonbacterial prostatitis are largely unknown, but bacterial prostatitis is caused by infection with uropathogens, especially gram-negative bacilli, although infection is sometimes due to gram-positive and atypical microorganisms. Acute bacterial prostatitis is easily diagnosed (by abrupt urogential and often systemic symptoms, along with bacteriuria) and treated (by systemic antibiotic therapy). Chronic bacterial prostatitis is characterized by prolonged or recurrent symptoms and relapsing bacteriuria; diagnosis traditionally requires comparing urinary specimens obtained before with specimens obtained after prostatic massage. Treating chronic bacterial prostatitis requires prolonged therapy with an antibiotic that penetrates the prostate (ie, one with high lipid solubility, a low degree of ionization, high dissociation constant, low protein binding, and small molecular size). We review recent pharmacological and clinical data on treating bacterial prostatitis.