AbstractThe tomb of King Djoser (2667-2648 B.C) at Saqqara known as the Step Pyramid was the first Egyptian pyramid tomb and the earliest stone building of its size in the world. Some of the walls of the substructure of the Step Pyramid and the so-called “Southern Tomb” were covered with panels of blue-green faience tiles. The present work aims to study causes of decay the faience tiles which coated Southern Tomb of Step Pyramid. Investigations and analytical techniques including scanning electron microscopy combined with energy-dispersive X-ray microanalysis (SEM/EDX), X-ray diffraction (XRD), X-ray florescence (XRF) and polarizing microscopy were used to study the chemical and mineralogical composition of different samples from bodies of faience tiles, stone supported walls and binding mortars.