Objective To investigate the correlation between bladder wall thickness (BWT) measured by ultrasonography and lower urinary tract dysfunction (LUTD) in patients with lower urinary tract symptoms (LUTS). Methods Forty-eight women with LUTS who underwent urodynamic study and BWT by ultrasonography as outpatients were studied. We assessed LUTS during a medical examination by interview. The thinnest part of the bladder wall was measured by a transabdominal ultrasonography. We excluded patients who had visited another hospital previously because we did not know what treatment they had received, including medications, behavioral therapy, or other treatments. We constructed receiver operating characteristic (ROC) curves for diagnosis of LUTD and also determined reliable BWT criteria by calculating the area under the curve. Statistical analyses were performed using the Kolmogorov-Smirnov method and Student's t-test. Results The mean age, body mass index, and duration of symptoms were 59.9±9.7 years, 26.06±3.4 kg/㎡, and 53.4±38.2 months, respectively. Urodynamic study parameters (Valsalva leak point pressure, maximal urethral closure pressure, functional length, and postvoid residual volume) were lower in patients with BWT <3 mm; however, these differences were not significant. Patients with BWT ≥3 mm developed a hypoactive bladder (P=0.009) and intrinsic sphincter deficiency (ISD) (P=0.001) at a significantly higher rate. According to the ROC analysis, the best BWT cut-off value was 3 mm for overactive bladder diagnosis. Conclusion Women with LUTD showed higher BWT values (≥3 mm), especially patients with hypoactive bladder and ISD. Sonographic evaluation of BWT is an easy, fast, and noninvasive method for possible diagnostic tool for LUTD.