To make clear the mechanism of wound healing in vocal cords which vibrate frequently during phonation and respiration, the laryngeal wound was artificially made in canine vocal cords and laryngeal cartilages by the laryngofissure approach. The healing process of laryngeal wound was studied biochemically and histopathologically. The results obtained were as follows : 1) The tissue hydroxyproline content increased continuously to the maximum value for 17 days after wounding, and then, it showed no change or slight decrease. 2) The changes in the tissue hydroxyproline content were not affected by the severity of wounds. 3) Histopathologically, marked proliferation of plump fibroblast was observed in 14 days after wounding and coincided with the increase in the hydroxyproline content. 4) The plump fibroblast was replaced with the collagen fiber and the epithelization was completed in 20 days after wounding.