PURPOSE: to evaluate the impact of voice disorders on quality of life of patients with idiopathic Parkinson's disease and with adductor spasmodic dysphonia. METHOD: the study consisted of 56 females, 28 in the control group; 14, the adductor spasmodic dysphonia group in the period prior to treatment with botulinum toxin; and 14, the group of idiopathic Parkinson's disease. The participants filled in the Voice-Related Quality of life (V-RQOL) questionnaire validated for Brazilian Portuguese. To check the difference between averages of the groups it was used the method of analysis of variance by Kruskal-Wallis and Tamhane test for multiple comparisons, with significance <0.05. RESULTS: the average age of the groups were 66.18 for the control group, 67.21 for the Parkinson's disease group and 59.7 for the adductor spasmodic dysphonia group, with no statistical difference between the groups. In the V-RQOL protocol the mean domain social-emotional, physical functioning and total score were higher in the control group, followed by group of Parkinson's disease and, finally, the group of adductor spasmodic dysphonia with statistically significant difference between them. In addition, there was statistical difference for each pair of groups, concerning the areas V-RQOL protocol, except as regards the pair control and Parkinson's disease group in the social-emotional domain (p= 0,076) CONCLUSION: the negative impact of voice on quality of life is greatest in the adductor spasmodic dysphonia group, followed by Parkinson's disease group and at last, the control group.