Elevated cardiac troponin I or T levels are caused by cardiac injury. Such elevations in patients with acute coronary syndrome are crucial in terms of diagnosis, risk stratification and guiding therapy. Cardiac troponins are also often elevated in patients with chronic renal failure and in a wide range of other medical conditions in which the pathophysiology of acute coronary syndrome (plaque rupture and thrombosis) is not present. This review discusses the differences between cardiac troponin and other cardiac markers and the importance of bedside testing. The literature on elevated cardiac troponins in patients with acute coronary syndrome, patients without acute coronary syndrome and patients with chronic renal failure is summarized. The significance of elevated cardiac troponins in each group as it relates to prognosis and guiding treatment options is discussed.