PURPOSE: Intravesical prostatic protrusion (IPP) is a morphological change of prostate protruded into bladder and might be related to bladder outlet obstruction (BOO) depending on the extent of protrusion. There is a high possibility that lower urinary tract symptoms (LUTS) tends to get worse as IPP grows. Therefore, it is necessary to examine the effect of IPP on LUTS after revision of prostate volume in order to identify the direct effect of IPP on BOO and LUTS. MATERIALS AND METHODS: A retrospective study of 296 male patients diagnosed with benign prostate hyperplasia (BPH) between August 2006 and December 2008 were performed. The patients were evaluated with international prostate symptoms score (IPSS) and quality of life (QoL), uroflowmetry (UFR), post-void residual urine volume (PVR), prostate volume and IPP as measured by transurectal ultrasound (TRUS). The changes of IPSS after 8 weeks of medication treatment and the occurrence rates of transurethral resection of prostate (TURP) and acute urinary retention (AUR) were compared. By checking IPSS and UFR, the improvement of voiding symptom was evaluated. RESULTS: The population of patients with moderate enlargement (30-50gm) of prostate extent was 147 (49.6%) out of 296, the whole examined population. There were correlation between IPP and IPSS (p=0.002) and the storage symptoms score was significantly increased (p=0.014). After 8 weeks of medication treatment, both moderate BPH patients with IPP showed similar improvement in storage symptom compared to non-IPP groups. But, the TURP was significantly performed more with IPP (p=0.040) than non-IPP groups and more AUR has occurred (p=0.013). After TURP, IPP group resulted in improvement of IPSS, storage symptoms score and voiding symptoms score statistically compared to non-IPP group. As the change of UFR and IPSS after TURP had shown, the improvements of voiding volume, maximal flow rate (Qmax), and average flow rate (Qavg) in IPP groups were smaller however, it is no correlation in statistical view. CONCLUSIONS: Moderate BPH group with IPP has a higher possibility of having AUR and surgical treatment while showing significant correlation with storage symptoms. A further prospective study is necessary for identification of improvement of IPSS and UFR after TURP and IPP should be checked carefully during TRUS.