Multislice computed tomographic coronary angiography (MSCT) can accurately detect the presence of atherosclerosis noninvasively. However, a discrepancy has been observed between MSCT and noninvasive functional imaging. The purpose of the present study was to evaluate the correlation between MSCT and invasive fractional flow reserve (FFR) in men with known coronary artery disease. Thirty-three patients (mean age 57 ± 11 years) clinically referred for coronary angiography underwent MSCT and FFR analysis. Coronary angiography and MSCT were evaluated for nonsignificant (30% to 50% luminal narrowing) and significant (>50% luminal narrowing) stenosis. Abnormal FFR was defined as ≤0.75. A total of 36 vessels were evaluated for FFR, with 8 (22%) showing reduced FFR. Results on MSCT were normal (completely normal or <30% luminal narrowing in 11 vessesl [31%], nonsignificant lesions in 13 vessels [36%], and significant stenoses in 12 vessels [33%]). Abnormal FFR was observed in only 58% of vessels with lesions >50% on MSCT. Nevertheless, the agreement between normal results on MSCT and normal FFR was excellent; FFR was normal in all 11 vessels with normal results on MSCT. In conclusion, significant stenoses on MSCT frequently do not result in reduced FFR. Normal results on MSCT, however, can accurately rule out the presence of hemodynamically significant lesions in men with known coronary artery disease.