Background　The　enlarged　prostate　leads　to　obstruction　and　lower　urinary　tract　symptoms　(LUTS),　which　comprise　frequency,　urgency,　weak　stream,　straining　and　nocturia.　This　study　was　conducted　in　a　large　series　of　patients　to　evaluate　the　relationship　between　LUTS　as　stipulated　in　the　International　Prostate　Symptom　Score　(IPSS)　and　the　objective　parameters　related　to　benign　prostatic　hyperplasia　(BPH).　Methods　We　enrolled　1295　BPH　patients　from　seven　centers.　The　patients　were　either　at　first　diagnosis　of　BPH　or　had　discontinued　medical　treatment　for　at　least　3　months.　Those　with　several　other　diseases　that　may　be　potential　risk　factors　affecting　urinary　symptoms　were　excluded　from　the　study.　Age,　IPSS,　prostate　volume,　peak　flow　rate,　urine　volume　and　post-voiding　residual　urine　volume　were　measured.　The　relationship　between　IPSS　and　objective　parameters　were　quantified　by　means　of　Spearman　correlation　coefficients.　The　differences　in　these　parameters　between　the　groups　with　mild,　moderate　or　severe　symptoms　were　also　evaluated.　Results　Statistically　significant　correlations　were　found　between　IPSS　and　objective　parameters　by　means　of　Spearman　correlation　coefficients.　When　the　patients　were　divided　into　three　groups　with　different　severities　of　symptoms,　there　were　significant　differences　in　peak　flow　rate,　urine　volume,　prostate　volume,　residue　urine　volume　and　quality　of　life,　whereas　average　age　and　prostate-specific　antigen　levels　were　similar.　However,　there　was　evident　overlap　of　these　parameters　between　the　groups.　The　same　results　were　found　when　the　irritative　or　obstructive　subscore　of　IPSS　was　considered.　Conclusions　The　correlation　between　objective　parameters　of　BPH　and　LUTS　is　significant.　However,　it　is　hard　to　predict　the　severity　of　symptoms　by　these　parameters.