Coronary angioplasty (PTCA) of total coronary occlusion is limited by the inability of guidewires and conventional dilating catheters to cross all such lesions. A new technique was therefore prospectively evaluated for PTCA of these lesions using the ultra-low-profile Probe "balloon on a wire" device. An intracoronary Probing Catheter was used to facilitate crossing the stenosis with a guidewire and then to deliver a Probe into the obstruction for balloon dilatation. This technique was utilized in 64 consecutive patients with "absolute" coronary occlusions demonstrating no angiographically detectable antegrade coronary flow. Successful dilatation was achieved in 47 (73%). Among 33 occlusions of less than 3 mo duration 31 (94%) were successfully dilated whereas only 16 of 31 more chronic occlusions were dilated (P less than .01). Chronic occlusions with a tapered morphology and those located more than 1 cm from a branch point were more frequently dilatable. There were no serious complications including no vessel perforations with this technique. The Probing Catheter technique offers a safe and effective method for the dilatation of recent coronary occlusions by using balloon on a wire technology.