Background and Objectives : Temporary or permanent vocal paralysis can be occurred after head and neck surgery such as thyroid cancer, esophageal resection, and chest operation including lung parenchymal resection, due to a vagus or recurrent laryngeal nerve injury. The authors aimed to determine the clinical efficacy of using Calcium-Hydroxyapatite (CaHA) for permanent unilateral vocal cord palsy patients. Materials and Method : Between July 2008 to July 2010, among patients with chief complain of hoarseness and aspiration, only who were diagnosed as unilateral vocal cord palsy under laryngoscopy, were selected. The patients included 3 females and 13 males age range between 29 to 79 and average age was 60 years old. Results : The hoarseness range were $8.94{pm}0.77$, $4.63{pm}1.02$, $4.31{pm}1.30$ statistically showing significant postoperative improve at preoperative, 1 week and 3 months. Also aspiration were $7.44{pm}2.48$, $3.63{pm}1.82$, $3.19{pm}1.91$ statistically improved during the same period. The result of voice analysis showed that the frequency range shows decrease at 1 week and 3 months after the injection compared to that of the preoperative result in both male and female group (Male: $161.63{pm}32.78$ Hz, $139.13{pm}30.63$ Hz, $146.67{pm}34.20$ Hz ; Female: $244.62{pm}26.62$ Hz, $244.91{pm}42.03$ Hz, $237.50{pm}38.95$ Hz). The Maximal phonation time were $2.75{pm}1.06$ (sec), $8.88{pm}3.46$ (sec), $8.44{pm}3.71$ (sec) statistically showing significant postoperative improve at preoperative, 1 week and 3 months. Conclusion : Injection laryngoplasty with CaHA in unilateral vocal cord paralysis is very safe and efficient procedure to improve a voice disorder, a swallowing difficulty, and a quality of life for those patients with a sacrificed RLN, a cancer invasion of the nerve, and a prolonged vocal cord paralysis which is more than six to twelve months.