To objectively determine the incidence of dysphagia associated with unilateral vocal cord immobility (UVCI) and to evaluate the potential for response to vocal cord medialization, we made videofluoroscopic swallowing (VFS) recordings of patients with newly diagnosed UVCI and prospectively analyzed them in a blinded fashion using the Penetration-Aspiration Scale (PAS) and pharyngeal transport function measures. A subset of patients underwent vocal cord medialization and were evaluated with a postoperative VFS study. Comparison was made between preoperative and postoperative VFS results to study the effects of vocal cord medialization in this setting. Eighty-seven VFS recordings were studied in 64 adult patients with UVCI; 23 patients underwent VFS testing before and after vocal cord medialization. The UVCI was most commonly left-sided (53 cases) and most commonly resulted from thoracic or cardiac surgery (53.1%), followed by malignancy (15.6%). Overall, the median PAS score was 2.0 (25th-75th percentiles, 1.0-5.0), with 20 patients (31.3%) and 15 patients (23.4%) exhibiting penetration or aspiration, respectively. No significant differences in swallowing function were noted between surgical and nonsurgical causes of paralysis (PAS scores of 2.0 and 2.0, respectively; p = .901). The median PAS score improved from 4.0 to 3.0 (p = .395, Wilcoxon paired samples test) in patients studied after undergoing a vocal cord medialization procedure (6 laryngoplasties and 17 vocal cord injections). Laryngoplasty was not more successful than vocal cord injection in resolving aspiration (p = .27). Radiographically significant penetration or aspiration occurs in approximately one third of patients with UVCI, independent of the cause of paralysis. Vocal cord medialization may not be as effective as thought for eliminating aspiration in these patients.