Apart from the identification of cocaine itself, there is a need to compare different seized cocaine samples to see if their "fingerprint" composition (i.e., the presence or absence of relevant minor constituents and their relative abundance) can be matched so as to establish whether the samples have a common source. In the Netherlands Antilles, all material suspected of containing cocaine, seized by either the police or customs authorities, was brought to the authors' laboratory for examination. The presence of cocaine in such seizures could be easily established by infrared spectroscopy, color tests, and other tests, but these techniques reveal little or no information about the minor components in the sample. The latter can be clearly visualized by thin-layer chromatography and gas chromatography. The frequently encountered minor alkaloids and other cocaine-related substances in the illicit cocaine samples seized were anhydromethylecgonine, tropacocaine, benzoylecgonie, cis- and trans-cinnamoylcocaine, norcocaine, the trxillines, N-benzoylnorecgonine methyester, and N-formynorcocaine. Each of these cogeners is discussed and evaluated for its use as a fingerprint parameter in cocaine analysis. 1 table, 4 figures, and 29 references