The stepwells define the subterranean architecture of Western India. The term stepwell indicates the basic architectural features of a monumental well comprising of a long corridor of steps leading to five or six storeys below the ground to a well. From the 7th to the 19th century, stepwells were an integral part of the Western India. Stepwells are a response to arid regions of Western India particularly in Gujarat and Rajasthan where water is treated as a sacred element which defines the lives, myths and rituals of the people. The stepwells of Gujarat are exceptional in their monumental scale and details. One of the magnificient stepwells is located near Ahmedabad known as Rani ki Vav. The construction of this stepwell began in 1063 A.D and probably it took some ten to twenty years to complete its construction that is upto 1085 to 1090 A.D. It is constructed of bricks and decorated with stone sculptures. It measures 64m long 20m wide and 27m deep. It has the four essential components which are seen in completely developed stepwells : a staircase leading from the ground level to the underground basin, intercepted at regular intervals with multistoreyed pillared pavilion, a well at the rear end, and a large tank or kund to store the surplus water from the well. This Vav also has bracing structures just above the tank, as an extra precaution against lateral thrust. The side walls of the staircase have niches and the wall surface of the well are adorned with beautiful sculptures. The stepwell was in use during the 12th and the 13th century, during the reign of Sidharaja. During this period the niches in the stepwell were filled up with marble sculptures.Later in the 13th century huge amounts of sand and silt were deposited in the well due to major floods of the Saraswati river which flows adjacent to this well. Other floods gradually silted up the entire well. Historical records mention that the well was functional and periodically desilted. The well was buried for centuries under the soil. The Archaeological Survey of India undertook the major task of desilting and restoration of Rani ki Vav which was declared a protected monument of national importance in 1940s. Desilting of the stepwell was commenced in 1960 A.D. Extreme care was taken while resetting of the architectural members and fixing the sculptures in their proper position. The conservation works were aimed at retaining the authenticity and the integrity of the monument during the restoration works. The stone used in the construction of this Vav is sedimentary sand stone varying from fine grain to coarse grained structure. Several test such as wet chemical analysis,X ray analysis,soil analysis etc were undertaken to understand the weathering of the stone. Today Rani ki Vav reveals its original grandeur and stands testimony to the expert craftsmanship and technology of the builders of the 11th century. This paper aims to bring forth the significance of this unique typology of stepwell and the continuing efforts undertaken by Archaeological Survey of India for restoring this historic monument.