OBJECTIVES The aim of this study was to evaluate outcomes in our department after surgery for obstructive hypertrophic cardiomyopathy and to establish the impact of a delay on the indication for surgery. METHODS From January 1998 to February 2011, 69 patients with obstructive hypertrophic cardiomyopathy and left ventricular outflow tract obstruction at rest were operated on by the same team, and followed up for at least 1 year. We retrospectively analysed clinical data, echocardiography and ambulatory Holter electrocardiogram findings before surgery, early after surgery, at 3 months and annually at follow-up, to detect possible prognostic determinants. RESULTS We performed isolated septal myectomy in 59 patients and a combined procedure in 10 patients. Mean outflow tract gradient decreased by 72.2 mmHg (SD 37.3) and there was a mean reduction in thickness of 8.2 mm (SD 5.8) in the interventricular septum. Functional capacity, measured as New York Heart Association class, and angina of effort improved significantly after surgery (P < 0.0001). In-hospital mortality rate was 1.44% for isolated myectomy and 4.35% for combined procedures. Global actuarial survival at 5-year follow-up was 87.4%, but if those patients who were in functional class II or less at the time of surgery were considered, survival rose to 100%. However, 43 patients (62.3%) with functional class III or higher were operated upon. CONCLUSIONS Clinical, haemodynamic and mortality outcomes after surgery were excellent, especially in those patients with mild or few symptoms. However, in our location, surgery is still undertaken at an advanced stage of the natural history of the disease, which may adversely affect prognosis.