Abstract Aim Describe the mechanism(s) of residual or recurrent obstruction in patients who have previously undergone septal myectomy for hypertrophic cardiomyopathy and assess early outcomes of reoperation. Method From January 1989 to March 2022, we performed 73 repeat myectomies at our institution. Patients’ demographics, operative details, echocardiographic parameters, and postoperative complications were retrieved from a prospectively maintained surgical database and electronic healthrecords. Results Median age at reoperation was 48.3 years (IQR 38.6-58.6); 51 patients were women (69.9%). 90.4% presented with NYHA class III/IV symptoms. Median interval between previous myectomy and reoperation was 2.7 years (IQR 1.2-4.5). Mechanism of obstruction was an inadequate length of previous septectomy in 41 patients (56.2%), a combination of inadequate length and midventricular obstruction in 30 (41.1%), and isolated midventricular obstruction in 2 patients (2.7%). There were no instances of recurrent LVOT obstruction due to muscle regrowth at the site of previous resection. All patients had an extended transaortic septal myectomy; 14 patients (19.2%) had concomitant transapical myectomy. Preoperatively, the median LVOT gradient was 83 mmHg (IQR 60-122), which reduced to 2 mmHg (IQR 0-7) following repeat myectomy. There were no perioperative deaths. Postoperatively, 4 patients (5.5%) developed a new CHB, necessitating PPM implantation. The 5-,10-, and 20-year survival after reoperation were 100%, 91%, and 76%, respectively. Conclusions Inadequate resection at the time of primary septal myectomy is the commonest cause of residual or recurrent obstruction in oHCM patients. However, repeat myectomy, including a combined transaortic and transapical approach has minimal risk with excellent hemodynamic and long-term survival outcomes.