The eligibility for subcutaneous implantable cardioverter-defibrillators (S-ICD) was assessed among patients already implanted with cardiac resynchronization therapy (CRT). We included 20 patients (15 men, age 73±10years, LVEF 35±10%). Seventeen (85%) patients were eligible for S-ICDs: 11 (55%) patients on only 1 vector and 6 (30%) patients on 2 or 3 vectors. Patients who were eligible on 2–3 vectors had narrower paced QRS than patients who were not eligible or were eligible on only one vector (133±18ms vs 167±17ms, p=0.007). If necessary, S-ICD implantation could be considered in most patients with CRT.