Dysarthria and phonatory symptomatology are often reported by patients suffering from multiple sclerosis (MS), but have been poorly investigated, although related to life quality. The objective of the study was to investigate the phonatory function in MS patients using objective measures. The speech of 64 MS patients and 64 pair-matched controls was recorded and analyzed using electroglottography, a physiological method that measures the electrical conductance during the opening and closing phases of the vibrating vocal folds. Electroglottographic parameters were correlated with clinical and MRI features. Most of the variables that have been used for the analysis of voice (vocal jitter P = 0.041, standard deviation of the average fundamental frequency P = 0.018, and the mean fundamental frequency of the vibrating vocal folds P = 0.025) differentiated the MS group from the control group. Phonatory function is impaired in MS patients, and physiological methods, such as electroglottography, are useful tools to assess it.