Hypoplastic coronary artery disease is a rare congenital abnormality reported to be associated with myocardial infarction and sudden cardiac death. Provoked positive spasm in the left circumflex coronary artery (LCX) with pharmacological spasm provocation tests was remarkably lower than other coronary arteries. We sometimes encountered patients with rest angina and hypoplastic right coronary artery (H-RCA). Among 5953 patients with diagnostic and follow-up coronary arteriography, we found 93 patients (1.6%) with H-RCA. During the same period, we could perform spasm provocation tests in 564 patients with rest angina including 13 patients with H-RCA and 249 patients with effort angina including 10 patients with H-RCA. Pharmacological spasm provocation tests were performed in 51 of 93 patients including 34 patients with ischemic heart disease (IHD) and 17 patients with non-IHD. Provoked spasm incidence in patients with IHD was higher than in those with non-IHD but not significant (52.9% vs. 29.4%, p = 0.1114). Provoked positive spasm in the LCX in patients with rest angina and H-RCA was significantly higher than that in those without H-RCA (69.2% vs. 23.4%, p < 0.001). Provoked spasm on both left anterior descending artery and LCX in patients with rest angina and H-RCA was also remarkably higher than in those without H-RCA (53.8% vs. 3.1%, p < 0,001). There were no clinical differences between patients with and without H-RCA rest angina. Two-vessel spasm (61.5% vs. 0%, p < 0.01) and LCX-provoked spasm (69.2% vs. o%, p < 0.01) were significantly higher in patients with H-RCA and rest angina than that in those with H-RCA and effort angina. In patients with rest angina and H-RCA, LCX-positive spasm was significantly higher and these patients may have a potential of high disease activity in the clinic as a coronary spastic angina.