Chronic heart failure is common and can be described as a syndrome characterized by impairment of cardiac function associated with a maladaptive metabolic and neurohormonal axis. The thesis that testosterone replacement therapy may be helpful as a treatment for chronic heart failure may seem at first to be unlikely. Testosterone therapy is widely believed to be deleterious to the cardiovascular system and there is a common misconception that the excess of ischaemic heart disease in young and middle-aged males compared to females is a direct effect of endogenous serum testosterone levels. In this chapter we will present the published evidence of the effects of endogenous and therapeutic testosterone on the heart and the human cardiovascular system with an emphasis on the pathologic syndrome of chronic heart failure. There is developing evidence that of all morbid populations, patients with chronic heart failure in particular are likely to benefit from testosterone treatment since the natural history is that of progressive disordered metabolism with catabolic excess and androgen imbalance.