The authors studied in dynamics the concentration of uric acid in 84 patients in the acute stage of myocardial, in 28 patients with non-stable stenocardia. The average value of uricemia, in the first 1--2 days post infarction is 6.35 +/- 2.23 mg%, considerably higher than that in case of non-stable stenocardia--4.75 +/- 1.25 mg%. In all the patients with myocardial infarction, 34.04 per cent have uricemia over 6 mg% (upper limit of the norm). The hypouricemia was normalized by the 14--15 day after the onset of infarction--4.25 mg%. The highest values of uric acid (up to 13 mg%) were found in case of severely progressing infarctions. A parallelism was established between serum concentration of uric acid and the creatinine-phosphokinase level. The possible pathogenic mechanisms of hyperuricemia in the acute stage of myocardial infarction are discussed.