BACKGROUND: While permanent dysphonia is a rare complication of thyroid or parathyroid surgery, postoperative changes of the speaking and/or singing voice often remain unrecognized. METHODS: In a prospective 4-arm study, vocal fold videolaryngostroboscopy and functional assessment of pre- and postoperative vocal performance was used to evaluate voice disturbances in 120 patients undergoing extended cervical surgery and in 19 patients with limited interventions for thyroid and/or parathyroid pathology. RESULTS: Impairments, especially of the singing voice, were predominantly observed after extended endocrine neck surgery. In women, the highest pitch of the singing voice (HPS) dropped from 651 Hz to 563 Hz (E5 to Csharp5, P < .001). In men, the HPS decreased to a lesser extent (423 Hz to 374 Hz, (Gsharp4 to Fsharp4, P = .009). Covariant analysis of influencing factors revealed the preoperative maximum frequency range and the HPS as predictors of the postoperative voice outcome. CONCLUSIONS: While alterations of the speaking voice after thyroid and parathyroid surgery usually remain subclinical, transient changes of the singing voice will matter to voice professionals.