PURPOSE: Voice change after thyroidectomy has generally been the result of damage to the recurrent or superior laryngeal nerve. But many patients complain voice alteration without laryngeal nerve injury after thyroidectomy. The purpose of this study is to investigate whether strap muscle division results in any subjective or objective functional sequelae in voice, through long-term follow-up prospectively. METHODS: Twenty-two female patients who had undergone thyroid surgery between July 1998 and December 1999, were studied. The patients who were planned for neck dissection, who had benign laryngeal disease or vocal cord paresis, and whose vocal cord paresis were developed after thyroid surgery, were excluded from this study. Twelve patients had undergone thyroidectomy via retraction of strap muscle and ten patients had undergone thyroidectomy via cutting of strap muscle. For evaluation of voice, questionnaires for changes of voice, acoustics (fundamental frequency, jitter, shimmer, signal to noise ratio, noise to harmonic ratio, voice range), and aerodynamic (maximal phonation time) analyses were done. RESULTS: The subjective voice symptoms after thyroidectomy were disturbances of high pitch, singing, loud voice, and easy fatigue at phonation. There were no significant differences in voice parameters on acoustic and aerodynamic analyses between the strap muscle retraction group and the cutting group through long-term follow-up. CONCLUSION: We conclude that strap muscle division does not result in any subjective or objective functional problems in voice. We suggest that surgical division and reconstruction of these muscles should be employed routinely when operating on large, toxic or neoplastic glands.