Coronary bypass surgery is well into its third decade. The randomized trials of saphenous vein grafting together with the various registries[57-60] have provided us with a wealth of information not only on the effects of surgery but also on the natural history of coronary heart disease itself. Numerous improvements have been introduced, the most notable being the use of the IMA as an arterial conduit. Thus the results of the randomized trials which significantly influence our clinical decisions may not accurately reflect what modern surgery can now offer, especially to the type of patient being operated upon in the 1970s. Nevertheless the decision about whom to operate on probably will not change, at least in terms of clinical variables affected by the coronary anatomy and left ventricular function. But there is every expectation that the long-term clinical results of surgery will be better since graft patency has already been shown to have improved as a result of anti-platelet therapy and, most of all, by the IMA. We will never have a randomized trial to prove this, but experience to date justifies this conclusion. The other great change that has occurred during the last decade is angioplasty and hopefully the randomized trials will put this technique in perspective. But practice has already changed and surgery for single vessel disease is now much less commonly performed given the greater appreciation of the good prognosis with which this lesion is associated and the ease with which angioplasty can alleviate the symptoms it causes.(ABSTRACT TRUNCATED AT 250 WORDS)