To describe the treatment of a subchondral bone cyst in the proximal phalanx with parathyroid hormone peptide-enriched fibrin hydrogel in a warmblood filly. The cyst was localized with computer-assisted orthopaedic surgery, then curetted and finally filled with parathyroid hormone fragment peptide 1-34 (PTH(1-34)) covalently attached to a fibrin hydrogel. The cyst healed quickly without any complications. This result supports the hypothesis that PTH(1-34) delivered locally in a fibrin hydrogel may improve the postoperative prognosis of surgical management of subchondral bone cysts in horses. Subchondral bone cysts are fairly common in horses. Especially in older horses, the prognosis is poor, even after surgical curettage. Therefore, different management protocols have been investigated in conjunction with surgical curettage to improve prognosis. Locally delivered PTH(1-34) seems to be a new method in the treatment of subchondral bone cysts.