Our preliminary experimental and clinical results with 201Tl myocardial scanning are presented. 48 patients with normal coronary vessels, acute trasmural myocardial infarction, localized and diffuse coronary heart diseases and congestive myocardiopathy were investigated. Results of scans and the usual cardiological investigations were in good agreement thus justifying further use of 201Tl myocardial scintigraphy as an adjunctive method in cardiology.