Methods: Seventy elderly patients with stable CHF, mean age 71 ± 8 years, ejection fraction 34 ± 1%, NYHA class II/III 38/32, were enrolled. Of these, 35 were randomized to receive testosterone therapy (through intramuscular injection every 6 week) and 35 to receive placebo both on top of maximal medical therapy. At baseline and after 12 weeks all patients underwent echocardiogram, cardiopulmonary test, 6-minute walking test (6MWT), quadriceps maximal isometric and isokinetic strength.