OBJECTIVES:The International Prostatic Symptom Score (IPSS) evaluates the frequency of symptoms associated with lower urinary tract symptoms (LUTS). An eighth question (q8) evaluates the patient's overall satisfaction dealing with his urinary tract status but does not study in detail his bothersomeness. The SPI score (Symptom Problem Index) evaluates the degree of discomfort associated with each question on the IPSS. Our objective was to determine the relations between IPSS, SPI and quality of life IPSS item (q8) scores. METHODS: A cohort of 907 male patients with BPH has been monitoring by French general practitioners. The IPSS and SPI self-administered questionnaires have been evaluated on the 722 patients with complete data. Relationships between SPI, IPSS and q8 have been investigated through the correlation between those scores and by showing the individual answers dispersion of IPSS and SPI scores when one was fixed. RESULTS:The mean IPSS score was 12.6 +/- 6.4, the mean SPI score was 12.2 +/- 6.5. The correlation coefficient between the IPSS and SPI scores was 0.70 ; the scores from the two rating scales showed a very high variability. Q8 was also weakly related to SPI (r=0.56) and to IPSS (r=0.57). The response to the question on quality of life corresponded to highly varying SPI and IPSS scores. CONCLUSION: IPSS and SPI questionnaires do not collect the same information. One scale cannot be replaced by another. Quality of life question of the IPSS questionnaire isn't enough to capture all the aspects of bothersomeness explored by the SPI questionnaire. Among patients suffering from LUTS, the joint use of the IPSS and SPI seems appropriate.