The association between swallowing function and cough strength in patients with unilateral vocal fold paralysis (UVFP) is unknown. We evaluated the relationship between voluntary cough strength and dysphagia among patients with UVFP (UVFP group) by comparing their data with that of corresponding healthy participants (healthy control [HC] group) in a prospective observational study. From February 1st, 2018 to March 30th, 2019, we recruited patients with a voice disorder due to UVFP, who were referred to our university hospital. Patients with a history of laryngeal surgery, vagal nerve paralysis, or cardiac and respiratory failure were excluded. Descriptive and clinical data regarding swallowing, voice, and cough peak flow (CPF) were collected as a measure of cough strength. The UVFP group comprised six women and seven men (median age, 68.0 years), and the HC group comprised six women and eight men (median age 65.5 years). The groups differed significantly in the Eating Assessment Tool (EAT)-10 scores and CPF rates (P < 0.001). Among patients with UVFP, 84.6% had an abnormal EAT-10 score of ≥ 3. Additionally, 16.7% of the patients exhibited liquid aspiration with contrast medium on a videofluorographic swallowing study (VFSS). There was no correlation between the CPF values, EAT-10 scores, or the VFSS results. Therefore, patients with severe UVFP, whose condition had been fixed, had difficulties when swallowing (85% of cases), and some even presented with aspiration on VFSS (20% of cases), while receiving a regular diet.