With its historical remains and beautiful travertine formations, Ilgarini cave is important in terms of archaeobotany and natural sciences. In the left part of the cave there are 2 temples and 11 graves. These graves had 3 floors, and wooden materials were used between them. The purpose of the study was to identify the wooden materials taken from the graves in Ilgarini cave and to determine the lifetime of the people who lived in the cave by dating them dendrochronologically. In wood identification analysis, many thin sections were cut, and they were compared with reference wood sections. In dendroarchaeological analysis, tree-ring widths of oak wood were measured and a floating chronology was constructed. As a result of wood identification, we determined that 8 of the wooden materials were oak, and others were 1 chestnut and 1 yew. Oak wood was used between the floors of the graves, but the usage places of the others were not determined. The dating results indicated that 2 usage times of the specimens could be seen. Specimens 12 and 13 were used at around the same time along with specimen 1, and others were used long before them. The last ring of the floating chronology was dated to A.D.977 by dendrochronological methods. With this result we can conclude that the graves and archaeological remains were from the late Byzantine period. © TÜBITAK.