BackgroundDesmotomy of the accessory ligament of the superficial digital flexor tendon (AL‐SDFT) has been described for the treatment of superficial digital flexor tendon (SDFT) tendinopathy in Thoroughbred and Standardbred racehorses, and in event horses. To our knowledge, the outcome of this procedure has not been described in a population of warmblood horses.ObjectiveTo report on the outcome of treatment of SDFT tendinopathy in warmblood horses using tenoscopic desmotomy of the main part of the AL‐SDFT.Study designProspective observational case series.MethodsAll 62 horses included in the case series had uni‐ or bilateral SDFT tendinopathy within the metacarpal/carpal region. The following data were collected and analysed using crosstabulations: breed, age, sex, use, affected limb(s), duration of tendinopathy, lameness grade, type and size of the SDFT lesion, bi‐ or unilateral desmotomy, duration of surgery, intraoperative findings, intraoperative/post‐operative complications, duration of hospitalisation and outcome 24 months after surgery.ResultsForty‐six horses (75%) were sound with 31 (51%) of these horses performing at the same level as prior to injury. Recurrent SDFT injuries or persistent lameness was observed in 15 (25%) horses. Two horses (3%) developed septic tenosynovitis post‐operatively, one required euthanasia. Horses with lesions in the proximal third of the SDFT had a better outcome than those with lesions in the two distal thirds (OR = 4.71, 95% CI = 1.33–16.70).Main LimitationsThere were no control groups of horses with SDFT tendinopathy treated by conservative therapy, tenoscopic complete or conventional open desmotomy.ConclusionsTenoscopic desmotomy of the main part of the AL‐SDFT is a successful treatment for SDFT tendinopathy in warmblood horses, especially in proximal SDFT lesions.