According to the literature, prostatitis is a rare cause of prolonged fever without an apparent origin. However, this syndrome can be easily diagnosed using specific tests, either two-glass pre- and post-prostatic massage or the Meares-Stamey four-glass test. A retrospective study over a 5-year period (between August 1st 2006 and July 31st 2011) was performed. All patients who met the criteria for microbiological prostatitis were included and assigned to one of two groups, either a study group [paucisymptomatic infectious prostatitis (PIP)] or a control group [classic infectious prostatitis (CIP)]. Epidemiological, clinical, microbiological, and treatment-related variables were collected. A comparative study between both groups was performed. Thirty-nine patients were diagnosed with prostatitis. The main risk factors were unprotected anal intercourse, human immunodeficiency virus (HIV) infection, recent travel, and recurrent urinary tract infections. The most significant differences between the PIP (19 patients) and CIP (20 patients) groups were higher frequency of elevated inflammatory markers, higher frequency of monomicrobial etiology, and longer treatment. In monomicrobial prostatitis, the most common causative agents were coagulase-negative Staphylococcus spp., Escherichia coli, and Corynebacterium glucuronolyticum. According to the findings of this study, we believe that prostatitis should be included as a possible diagnosis in a man who complains of prolonged fever without an apparent origin and having at least one of the following risk factors: unprotected anal intercourse, HIV infection, recent travel, and recurrent urinary tract infections.