The electron impact mass spectrum of cocaine is familiar to most forensic drug chemists. Although mechanisms for the major mass spectral decompositions of this compound have been proposed, a systematic study of its fragmentations has never been conducted. At the same time, the literature is replete with mass spectra of cocaine derivatives, many of which are appropriate for gaining insight into the fragmentations of the parent molecule; however, until the recent paper by Casale, Moore, and Cooper, which describes the preparation of 6- and 7-chlorococaine, spectra for derivatives in which the two-carbon bridge of cocaine was functionalized were not available; this has limited knowledge of the fate of these carbons. This study used published mass spectral data, as well as one previously unpublished spectrum from the author's laboratory, for cocaine derivatives that show functional group modifications at the following locations: the nitrogen, the alkyl ester group, the aromatic ring, and the two- carbon bridge. Preference was given to deuterated derivatives, whose spectra should mirror those of parent compounds, and to compounds with functional groups that could act as "labels" without substantially altering the overall fragmentation of the tropane skeleton. In addition, an under-cited work by Shapiro et al. provides exact mass measurements as well as empirical formula for most of the significant ions in the cocaine spectrum. These data support some previously proposed fragmentation mechanisms and shed new light on others. These pathways are considered in the context of all the available data. 1 table, 8 figures, and 16 references