Vocal hyperfunction is considered to be the most significant characteristic in functional voice disorders which is found among many patients presenting hoarseness primarily as chief complaint. Many reports show adequate voice therapy improves disordered voice as these abnormalities due to either excessive tension of laryngeal muscle or inadequate breath support. In our hospital, voice therapy was performed on a group of 34 patients with hoarseness who had diagnosed as functional dysphonia and laryngeal noduel by employing methods such as history taking, indirect mirror examination, transnasal fiberoptic laryngoscopy and stroboscopy. Comparison study was conducted in control group who only recieved vocal hygiene and the results were evaluates by the measures consisted of patients' subjective evaluation, perceptual evaluation, laryngeal findings and acoustic analysis. In the group of functional dysphonia, 100% improvement was observed in the patients' self evaluation measures and overall 50% improvement relative to baseline was noted in the rest measures in voice therapy cases. No evidence of a specific benefit from therapy was identified in the control group. In the group of laryngeal nodule, patients' self evaluation, electroglottography, multidimensional voice program was more efficacious than other evaluation methods in voice therapy cases, and 44% improvement was observed in vocal hygiene group in both patients' self evaluation and perceptual evalution measures. The results of this study support the notion that voice therapy is indicated mainly in cases of functional voice disorders.