The identification of di(beta-phenylisopropyl)amine found as the main ingredient in several sets of amphetamine tablets sold on the illicit market in Rome, Italy, during 1999-2000 is described. The identification was achieved by examining the ultraviolet and nuclear magnetic resonance spectral properties as well as the chromatographic, gas chromatographic, and mass spectrometric data. The molecular structure of the ingredient showed a close analogy to the amphetamine and could very likely produce similar pharmacological activity. A preliminary test on the metabolic pathway of di(beta-phenylisopropyl)amine performed on rats, suggests its biotransformation to amphetamine.