Of 87 drug trafficking cases selected from the 1984-1997 period, 39 were included in the sample. Court records for each case were reviewed to obtain information on activities of drug trafficking organizations and their composition and operational methods. Cases were classified under a typology that included freelance, family business, communal business, and corporation categories. Significant variations in structure and tasks were found. In most cases, drug trafficking organizations seemed to specialize quite narrowly in the tasks undertaken, but there was only a weak relationship between organizational type and these tasks. Small freelance groups were a little more likely to be involved in tasks higher up the distribution chain, whereas larger organizations were somewhat more involved lower down. The largest corporate organizations were generally involved in drug dealing at the retail level. The results have important implications for future research and suggest the need for caution in generalizing from the findings of single case studies. The authors conclude that typology permits the systematic sampling of drug trafficking organizations for detailed study and indicate this is particularly important for policy since interventions must be closely tailored to the nature of criminal enterprises. Salient features of the 39 drug trafficking organizations are listed in an appendix. 48 references, 2 notes, 2 tables, and 1 figure