Data concerning learned voiding dysfunction (Hinman syndrome; non-neurogenic, neurogenic bladder) in adults are scarce. The present study was conducted to assess the pre-valence and clinical characteristics of this dysfunction among adults referred for evaluation of lower urinary tract symptoms. Learned voiding dysfunction was suggested by a characteristic clinical history and intermittent "free" uroflow pattern and by the absence of any detectable neurological abnormality or anatomic urethral obstruction. A definitive diagnosis was made by the demonstration of typical external urethral sphincter contractions during micturition by EMG or fluoroscopy. A urodynamic database of 1,015 consecutive adults was reviewed. Twenty-one (2%) patients (age, 24-76 years) met our strict criteria of learned voiding dysfunction. Obstructive symptoms were the most common presenting symptoms, followed by frequency, nocturia, and urgency. Eight (35%) patients had recurrent urinary tract infections, seven of these being women. None of the patients had any clinically significant upper urinary tract damage. First sensation volume was significantly lower in women than in men. Both detrusor pressure at maximum flow and maximum detrusor pressure during voiding were found to be significantly higher in men than in women. Further differentiation between adult women and men failed to reveal any other clinically significant differences. In conclusion, by strict video-urodynamic criteria, 2% of our patients had learned voiding dysfunction. Other patients, with presumed learned voiding dysfunction, who did not undergo video-urodynamics were not included in the present series. Thus, the prevalence of learned voiding dysfunction among adults referred for evaluation of lower urinary tract symptoms is likely to be even higher.