Obsidian was an important commodity in the Aztec empire. The obsidian industries from several Late Aztec sites in the northeastern Basin of Mexico are briefly summarized. These sites represent both urban centers and their rural dependencies. Site TA-80, the urban center of the Otumba city-state, contained numerous surface concentrations of obsidian debris, representing refuse from workshops where obsidian tools were produced or consumed. Seven of these concentrations represent debris from specialized production of large quantities of prismatic blades. Others represent workshops where blades were consumed in substantial numbers in the process of producing some other commodity. Households at rural sites in the Otumba city-state did not produce blades but probably obtained them through exchange from the specialized producers at TA-80. However, some rural sites did contain evidence of specialized quarrying, preparation of macrocores, and production of bifacial tools, apparently for export to urban centers. Similar evidence is found in the Tepeapulco city-state, which also had evidence of specialized production of prismatic blades in the urban center and of consumption of blades by both specialized producers of other commodities and in domestic contexts, in the urban center and at rural sites. Some rural sites in the Tepeapulco city-state, as in Otumba, also had evidence of specialized production of bifaces and macrocores. In both city-states, obsidian was extracted from local sources and shaped into macrocores and bifaces, which were then exported to the city-state center and to more distant locations beyond the boundaries of the city-state. Within the urban centers of each city-state, macrocores were reduced to prismatic blades. Large quantities of blades were produced by craft specialists, working at a few restricted locations within the city-state centers. The finished blades were then distributed to consuming households within the urban center of the city-state, as well as to rural dependencies and to more distant consumers beyond the boundaries of the city-state.