Objectives/Hypothesis Injection laryngoplasty of materials for unilateral vocal‐fold paralysis has shown various results regarding the long‐term stability of the injected material. We evaluated a fibrin‐gel based cell suspension with autologous chondrocytes in‐vitro and in‐vivo as long‐term‐stable vocal‐fold augmentation material in an animal model. Study Design This study compises an in vitro cell‐culture part as well as an in vivo animal study with New Zealand White Rabbits. Methods In in‐vitro experiments, auricular chondrocytes harvested from 24 New Zealand White Rabbits cadavers were cultivated in pellet cultures to evaluate cartilage formation for 4 weeks using long‐term‐stable fibrin gel as carrier. Injectability and injection volume for the laryngoplasty was determined in‐vitro using harvested cadaveric larynxes. In‐vivo 24 Rabbits were biopsied for elastic cartilage of the ear and autologous P1 cells were injected lateral of one vocal cord into the paraglottic space suspended in a long‐term‐stable fibrin gel. Histologic evaluation was performed after 2, 4, 12, and 24 weeks. Results During 12‐week pellet culture, we found extracellular matrix formation and weight‐stable cartilage of mature appearance. In‐vivo, mature cartilage was found in two larynxes (n = 6) at 4 weeks, in four (n = 6) at 12 weeks, and in five (n = 6) at 24 weeks mostly located in the paraglottic space and sometimes with spurs into the vocalis muscle. Surrounding tissue was often infiltrated with inflammatory cells. Material tended to dislocate through the cricothyroid space into the extraglottic surrounding tissue. Conclusions A cell‐based approach with chondrocytes for permanent vocal‐fold augmentation has not previously been reported. We have achieved the formation of structurally mature cartilage in the paraglottic space, but this is accompanied by difficulties with dislocated material, deformation of the augmentation, and inflammation. Level of Evidence N/A Laryngoscope, 131:E1624–E1632, 2021