Of 383 patients with vasospastic angina who were followed for a period of 3.2 +/- 0.1 years, 9 (2%) died suddenly from cardiac causes. Calcium antagonists had been given to 98% of our patients. Only one patient who died suddenly had a fixed coronary stenosis of 75% or greater. Eight of the 9 patients showed ST segment elevation during anginal attack at rest, and 3 patients showed ST segment elevation at both anterior and inferior leads. Sudden death occurred in 6 of 41 patients (12.5%) who were documented to have multivessel coronary spasm, but in only 3 of 342 patients (1%) who had single vessel spasm (p less than 0.01). Serious arrhythmia occurred during anginal episode in 3 of 9 patients who died suddenly (53%) and in 52 of 374 who did not (14%). These results suggest that the frequency of sudden cardiac death was rather low in Japanese patients with vasospastic angina. The risk of sudden death was increased in patients with multivessel spasm and serious arrhythmia during anginal attacks but not these with fixed coronary stenosis.