Background <p>In multiple sclerosis, lower urinary tract symptoms are frequently observed depending on the site of involvement. A comprehensive assessment of these symptoms is crucial for their effective management.</p> Objective <p>This research was designed to evaluate the validity and reliability of the Turkish adaptation of the Core Lower Urinary Tract Symptom Scale (CLSS) in patients with multiple sclerosis (PwMS).</p> Methods <p>71 PwMS who had an Expanded Disability Status Scale score of 6.5 or below was included. Data collection involved demographic information as well as responses to the CLSS, Overactive Bladder Questionnaire, Interstitial Cystitis Symptom Index, Interstitial Cystitis Problem Index, and International Prostate Symptom Score. To evaluate test-retest reliability, the CLSS was administered again under identical conditions after a 7-day interval.</p> Results <p>The internal consistency of the questionnaire was assessed, resulting in a Cronbach’s alpha coefficient of 0.79. Test-retest reliability for the CLSS sub-items ranged from 0.593 to 0.950. No statistically significant differences were found between the sub-items scores of the test and retest administrations. (<i>p</i> &gt; 0.05). Moreover, the subscales showed significant correlations with the other questionnaires, with correlation coefficients varying between 0.109 and 0.770. Straining, feeling incomplete emptying, and pain in the bladder sub-items did not show a significant correlation with the corresponding sub-items of other questionnaires (<i>r</i> = 0.109, 0.270, and 0.195, respectively).</p> Conclusion <p>The Turkish adaptation of the CLSS questionnaire has been proven to be a reliable and valid instrument for evaluating lower urinary tract symptoms in PwMS.</p> <p><b>Clinicaltrials.Gov Number</b>:&#xa0;NCT06599866.</p>