Radioisotope detection and localisation of myocardial infarction is discussed. Its clinical value and pitfalls are also discussed. The clinical application of this safe, simple, sensitive, repeatable, reproducible and non-invasive method in Malaysian patients performed during the period October 1978 to April 1979 at the University Hospital is reviewed. The main value of 99mTc labelled phosphate scan is in the demonstration and localisation of recent myocardial infarctions in patients where the electrocardiogram or serum enzymes changes are unhelpful.