Continuing an investigation of the epigeal part of Korolkowia sewerzowii Regel., the methanol mother solution from korseveriline and the acetone mother solution from korseveridine [1] were chromatographed separately on a column of alumina. Elution with chloroform-methanol (10:0.5) gave a base (II) with mp 150-152°C (acetone), [α]D -13° (c 0.7; chloroform), M+ 427. When (II) was acetylated with acetic anhydride in pyridine, a O,N-diacetyl derivative (IV) was obtained with M+ 511. A comparison of the physical constant and spectral characteristics of alkaloid (II) and of an authentic sample of petisidine [3-7] showed their identity (melting point of a mixture, Rf values, and IR, PMR, and mass spectra). This is the first time that petisidine has been detected in plants from the genus Korolkowia.