Sannur Cave, the largest subterranean chamber known in Egypt is situated about 70 ion to the southeast of Beni-Suef city in the remote Wadi Sannur of the Eastern Desert. Sannur Cave was first discovered during blasting in the alabaster quarry which caused an artificial entrance to the cave. The cave is a single crescent shaped chamber approximately 275m long. The cave is arbitrarily divided into two sections having different characteristics; leftside gallery and right side gallery. Few speleothems occur in the left side gallery while the right side gallery is decorated intensively with many kinds of speleothem. Based on the geologic, structural and morphologic observation inside and outside the cave, some interpretations on the paleoenvironment and the origin of the cave are made. Surveying was performed with GRADE 4C according to BCRA Gradings.