Magnitude-squared coherence (MSC) was used to detect 40-Hz auditory-evoked potentials (AEPs) in a two-alternative forced-choice experiment. MSC performance was found to be better than that of ten human observers. Experienced observers did not perform better than naive observers. In a ‘‘yes–no’’ experiment, observers demonstrated large differences in criterion, with false-positive rates of 2%–20%. Observers also performed better when AEPs were presented in a 50-ms window (two response cycles) than when presented in a 205-ms window (eight response cycles), although total test time was the same; MSC performed equally well in both cases. MSC provides a useful and objective adjunct to visual detection of 40-Hz AEPs.