BACKGROUND: Benign prostatic hyperplasia (BPH) is a common disease in older men and is often associated with enlargement of the prostate gland and lower urinary tract symptoms (LUTS).It causes bladder outlet obstruction (BOO) which leads to changes in bladder wall and function resulting in detrusor wall thickening and ultra-structural alterations. These changes in bladder wall are time-dependent and may reflect the severity of underlying BOO. Although urodynamic tests are considered to be the gold-standard for the assessment of severity of LUTS, these are time-consuming, invasive and expensive. DWT measurement has emerged as a cheap, noninvasive and reproducible alternative means of assessing the severity of LUTS in men with BOO. Several studies have been published revealing the predictive value of detrusor wall thickness (DWT) in assessment of men with BOO. Ultrasonograhic evaluation of DWT can serve as a diagnostic as well as prognostic assessment tool. OBJECTIVE: To determine the correlation of the DWT with IPSS during evaluation of men with LUTS in N.A.U.T.H, Nnewi. MATERIALS & METHODS: This is a hospital- based cross-sectional prospective study recruiting 100 new consecutive patients ≥ 40 years with LUTS attending Urology Clinics of the Nnamdi Azikiwe University Teaching Hospital (NAUTH). Patients who met the inclusion criteria and voluntarily gave their consent were interviewed to obtain useful information including the bio-data, co-morbidities as well as assessment of severity of LUTS using IPSS validated questionnaire. The DWT was measured by transabdominal USS at bladder volume > 250 ml. Severity of LUTS was assessed using a validated IPSS questionnaire which was incorporated in the study proforma. RESULTS: The mean age was 71.02+ 9.10 years with the mean duration of symptom being 30.63 + 26.60 (3.00 to 120.00) months. The International Prostate Symptom Score (IPSS) ranged from 10.00 to 32.00 with a mean of 20.94+ 6.13. Forty three patients (43.00%) and 57 patients (57.00%) had moderate (IPSS=8-19) and severe (IPSS=20-35) LUTS respectively. None of the respondents had mild LUTS (IPSS=0-7). The mean + standard deviation for anterior, lateral, dome and average DWT measurements were 4.95 +2.36 mm , 4.96 +2.37mm, 5.02 +2.34 mm and 4.98 + 2.35mm respectively. Ninety seven respondents (97.00%) had DWT ≥2mm. The average DWT correlated strongly with the IPSS (r2 = 0.635 and p<0.0001). There was a positive but weak correlation between the average DWT and the duration of symptoms (r2 = 0.497 and p<0.0001) as well as between the average DWT and the age of the patients (r2 = 0.004 and p<0.0001). CONCLUSION: In conclusion, the finding of a strong positive correlation between DWT and IPSS in this study has demonstrated DWT measurement as a cheap, noninvasive and reproducible means of assessing the severity of LUTS in men with BOO. However, there was a positive but weak correlation between DWT and other parameters like the age of the patients and duration of symptoms. With standardization of DWT measurement, DWT assessment holds a great deal of future hope and may likely replace other invasive tests in evaluation of patients with LUTS. Key words: IPSS, DWT, BPH, LUTS