To facilitate more rapid and safe measurement of coronary flow velocity reserve in patients, we developed a Judkins-style angiographic catheter tipped with a 20 MHz Doppler crystal. In 19 patients without coronary artery disease, resting and hyperemic (10 mg intracoronary papaverine) mean and phasic coronary flow velocity signals were measured with the Judkins-style and 2.5F intracoronary Doppler catheters at identical coronary loci. Mean coronary flow velocity at rest was similar (14 ± 8, 10 ± 7 cm/sec, p = ns), but was higher during hyperemia for the Judkins-Doppler (41 ± 8 versus 32 ± 14 cm/sec, p < 0.05). Coronary flow velocity reserve, calculated as the ratio of mean velocity reserve, calculated as the ratio of mean velocity at rest to mean velocity following papaverine, was 3.3 ± 1.4 and 3.7 ± 1.2 units (p = ns) for the Judkins and intracoronary Doppler techniques, respectively (r = 0.801, p < 0.001). The Judkins-style Doppler catheter technique permits flow velocity and coronary flow velocity reserve measurements that correlate strongly with those of the intracoronary catheter technique, facilitating safe, quick, and accurate assessment of coronary physiology.