Background:The human voice is one of the most important tools in human every day. Communication and voice were probably important to human communication even before language evolved. Voice Quality can be affected in patients with thyroid disease like, loss of vocal range, low speaking fundamental frequency (especially in women), coarse and gravelly vocal symptoms, weak voice, and breathy quality, reduced Intensity and changes of the singing voice.Purpose: The aim of this work is to identify auditory perceptual voice changes and Severity in patients with thyroid and/or parathyroid disease preoperatively.Methods: 60 adult subjects their age ranged between 20 and 60 years old, both males and females, divided into two groups were included (Group A): 30 patients diagnosed with thyroid and/or parathyroid Disease preoperatively. (Group B): 30 healthy normal subjects. Both groups were undergone to Modified GRBAS scale, Voice Recording, and Flexible nasofibrolaryngoscopy.Results: There is difference between the two groups regarding the presence or absence of dysphonia, chewing and swallowing, and parameters of APA (auditory perceptual assessment) except register. Conclusion:The perceptual measure of voice by modified GRBAS, revealed significant differences in (overall grade of dysphonia, pitch, and loudness, of voice) between the individuals with thyroid disease and those in an age and gender-matched control group. If surgeons can screen for pre-surgical dysphonia, the rate of indeterminate postsurgical dysphonia may be reduced, or at least explained and prepared for.