Abstract This study concerns three Mayan sites located on the eastern coast of the Yucatan Peninsula (Quintana Roo, Mexico): Chac Mool (Early to Late Post-Classic), San Miguelito (Late Post-Classic) and El Meco (Early to Late Post-Classic). A collection of 70 obsidian samples (blades and core fragments) from these sites was analyzed by neutron activation. Of these samples, 100% from El Meco, 97% from San Miguelito, and 93% from Chac Mool were identified as coming from the Ixtepeque Volcano and the rest from El Chayal, both obsidian sources in the Guatemalan Highlands. It seems that during the Middle and Late Post-Classic, the obsidian of Ixtepeque replaced the material of the other sources of the Highlands. It is clear that these sites formed part of the obsidian trade routes from these Highlands, which skirted the Coast of the Yucatan Peninsula and reached the Gulf of Mexico and other Pre-Hispanic sites.