Audio cassettes claimed by distributors to contain subliminal messages embedded within background sounds are currently-widely marketed and advertized. Although subliminal perception has generated considerable controversy for many years, recent research suggests that subliminal perception does occur when subjects can detect the presence of a stimulus but have no confidence that a stimulus was even presented. Given that the minimal stimulus condition for subliminal perception is stimulus detection, the subliminal audio cassettes marketed by several distributors were evaluated to determine if this condition was satisfied. Spectrographic analyses indicated that no identifiable speech is contained within the background sounds. In addition, using cassettes supplied by a major distributor, listeners could not distinguish between “signal” and “placebo” cassettes in a forced choice detection task. On the basis of these results, the only reasonable conclusion is that these audio cassettes do not contain any embedded subliminal messages that could conceivably influence behavior.