Nisoldipine is a new calcium channel blocker of the dihydropyridine family with a high affinity for coronary vessels. We assessed the efficacy of nisoldipine in the treatment of asymptomatic ischemia in 12 patients with chronic, stable angina. Two to four weeks of daily therapy with prn nitroglycerin and placebo was followed by 24-hour ambulatory electrocardiographic recording for ST segment assessment. After two weeks of once-daily nisoldipine, 10 to 20 mg, the ambulatory recording was repeated. A significant difference was seen in ischemia-magnitude products of asymptomatic ischemic episodes in placebo versus active drug periods (P less than .05). When total ischemic burden was considered (ST segment depression during both painless and painful episodes), the difference was even more significant (P less than .02).