The authors present data on sources of obsidian from the Levant, as indicated by neutron activation analysis of artifacts and source samples. The results are correlated with results obtained by Renfrew and Cann using optical spectrography through the analysis of source samples analyzed by both techniques. The three focal sites of Munhata, Beisamoun, and Hazorea are described briefly. Neutron activation techniques are then described by which Na, Mn, La, Sm, Fe, Rb, and Sc were determined. The discussion of results focuses on sources of the obsidian artifacts from the three sites and on changes in obsidian supply through time. Several sources were represented at each site. Anatolian sources were clearly dominant during Pre-Pottery Neolithic A and Pre-Pottery Neolithic B times, although a few pieces from the Lake Van region also reached the Levant before 6000 B.C. By 4000 B.C., obsidian was obtained from sources in Eastern and Central Turkey.