OBJECTIVE: To assess the prevalence of chronic prostatitis (CP) and chronic pelvic pain syndrome (CPPS) symptoms in a large group of men, using the National Institute of Health-Chronic Prostatitis Symptom Index (NIH-CPSI), and to evaluate which of the NIH-CPSI symptoms had the most detrimental effect on quality of life (QoL). SUBJECTS AND METHODS: The NIH-CPSI was completed by 1273 men during a male-health promotion event. The presence of CP/CPPS-like symptoms was defined according to the NIH-CPSI criteria (perineal pain or ejaculatory pain and NIH-CPSI-pain score >/= 4). Finally, using linear regression analyses we evaluated the effect of each questionnaire symptom on the NIH-CPSI-QoL domain. RESULTS: The mean (range) age of the men was 57.6 (40-89) years; 133 (10.5%) reported CP/CPPS-like symptoms, with 62 (4.9%) reporting mild and 71 (5.6%) reporting moderate to severe CP/CPPS-like symptoms. Men with CP/CPPS-like symptoms had higher NIH-CPSI-QoL scores, showing a greater detriment of QoL (4.9 vs 2.5; P < 0.001). Of all NIH-CPSI symptoms, urinary frequency was associated with the least favourable QoL, followed by incomplete bladder emptying, pain frequency and pain intensity. The individual pain location had no significant impact on the QoL. CONCLUSION: In a large healthy population CP/CPPS-like symptoms are common and have an important impact on QoL. Functional CP/CPPS-like symptoms have a greater detrimental effect on QoL than pain symptoms. Therefore, these symptoms should represent the main therapeutic targets in affected patients.