OBJECTIVE To our knowledge there are no studies of the correlation between urinary complaints or urodynamic findings in multiple sclerosis and magnetic resonance imaging (MRI) findings. We investigated the correlation of urodynamic results in multiple sclerosis patients with voiding complaints to the cranial MRI findings. We also sought to correlate urodynamic results in these patients with International Prostate Symptom Scores (IPSS). METHODS We retrospectively reviewed urodynamic results and cranial MRI findings in 90 multiple sclerosis patients (64 women, 26 men, mean age 44.5 years) with voiding complaints. The most recent urodynamic study and cranial MRI for each patient were reviewed. The interval between the 2 studies and MRI was no more than 6 months. Detrusor contractions were categorized as areflexic, hyporeflexic, hyperreflexic or hyperreflexic with impaired contractility. The presence of impaired compliance or detrusor-external sphincter dyssynergia was recorded. The cranial MRI findings were categorized on the basis of the presence of atrophy or enhancing lesions, total number of lesions and size of largest lesion. The urodynamic and MRI findings were correlated. Of the patients 40 who had urodynamic studies done within the last 6 months completed the IPSS, and severity of cranial MRI findings in these patients was correlated with the IPSS results. In addition, the presence of irritative findings of detrusor hyperreflexia or detrusor hyperreflexia with impaired contractility was correlated with the irritative score (sum of questions 1, 2, 4, 7), and the presence of detrusor-external sphincter dyssynergia was correlated with the obstructive score (sum of questions 3, 5, 6). RESULTS There was no correlation between urodynamic category, presence of impaired compliance or presence of detrusor-external sphincter dyssynergia and any of the MRI findings of atrophy or enhancing lesions, total number of lesions or size of the largest lesions. In the patients who completed the IPSS there was no correlation between total number of lesions and IPSS score. There was no correlation between the presence of detrusor-external sphincter dyssynergia and obstructive score on the IPSS or between the presence of detrusor hyperreflexia and irritative score. CONCLUSIONS Although patients with multiple sclerosis often are followed closely with urodynamic studies and cranial MRI, there appears to be no correlation between these 2 studies. Symptom scores also do not appear to correlate with urodynamic findings. Therefore, urodynamic studies appear to be warranted and irreplaceable in the evaluation of voiding dysfunction in multiple sclerosis patients.