Nearly 600 obsidian artifacts dating from about 200 b.c. to a.d. 950 at Quelepa, El Salvador, are assigned to geological source areas using visual criteria and an abbreviated neutron activation analysis (NAA) technique. This combined methodology affords highly accurate results, is inexpensive, and allows large collections to be sourced. Results of lithic analyses describe the evolution of procurement and production strategies at the site. Despite the location of the site on the far southeastern periphery of Mesoamerica, the lithic analyses indicate that Quelepa participated in a Mesoamerican rather than Central American transference network.