Ten hair samples of Copts from the 8th–10th century AD obtained during the 1963–1964 excavation campaign in the district of Sayala, and 11 hair samples of Egyptian mummies dated to the 18th–25th dynasty were examined for their structural properties compared with recent hair samples. Structural comparison was performed using X-ray diffraction and infra-red spectroscopy. Using the attenuated total reflection technique, which allows multiple reflection infra-red spectroscopy on native hair, we were able to reveal the structural integrity of the ancient hair samples. X-ray diffraction studies using Cr-alpha radiation confirmed the infra-red results. Signs of dehydration could be observed but no conformational changes, indicating the structural stability of hair protein over thousands of years.