OBJECTIVE To determine the normal values for the presumed circle area ratio (PCAR) in a group of community-based men, and to determine whether PCAR is associated with specific urological outcomes. PATIENTS AND METHODS The study was a cross-sectional analysis among 328 Caucasian men (94% participation) residing in Olmsted County, Minnesota, USA. The PCAR was measured during prostatic ultrasonography. Lower urinary tract symptoms (LUTS) were measured using the American Urologic Association Symptom Index. The peak urinary flow rate was measured by a uroflowmeter, and the postvoid residual volume (PVR) was assessed using the BladderScan(TM) BVM 6500 (Verathon, Bothell, WA, USA). Correlations between PCAR and presence of LUTS, peak urinary flow rate, and PVR were determined using Spearman correlation coefficients. Unadjusted and adjusted odds ratios (ORs) were calculated using logistic regression to determine the associations between PCAR thresholds and categorical urological outcomes. RESULTS The median (interquartile range) PCAR was 0.85 (0.81-0.88). After adjusting for age and total prostate volume, men who had PCARs of >0.90 were more likely to have elevated overall and obstructive symptom scores (OR 2.95, 95% confidence interval 1.39-6.25, and 3.47, 1.63-7.39, respectively). CONCLUSION PCAR might add further information beyond total prostate volume when predicting the development of obstructive LUTS.