Little has been published about the demolition of post-tensioned concrete but there is enough such concrete now in service to become a problem for demolition contractors. When a demolition sequence is being planned it is important to have a knowledge of the erection procedure and a set of the as-built record drawings. This fact of life was confirmed recently when 9 prestressed beams had to be demolished and extensive repairs made to other beams within the decks of bridges under construction for a highway in England. Exact identification of prestressing cables along each beam was of great importance in the demolition process and fundamental to the remedial stressing. The demolition method adopted was to reverse the construction sequence by isolating the affected beam and cutting it into the original simply supported segments. These segments were split further into half-lengths to ensure complete loss of prestress in the cables and to provide convenient 15 ton portions for removal by crane. First the cast in place reinforced concrete string course was removed by breaking out a longitudinal slot in the deck with heavy pneumatic hammers and burning through the transverse reinforcement with acetylene torches. The next step was to cut slots in the deck slab about 6 feet long by 12 to 18 inches wide over the position of the intermediate diaphragms. The slots were situated close to the edge of the upper flange so that the transverse deck steel could be cut with the maximum lap length available for connecting into the replacement beam. The longitudinal slot in the deck was extended adjacent to the beam for its full length except for bridging pieces 30 inches wide. Pier and end diaphragms were broken out at virtually the same time, with an effort again being made to leave the main diaphragm steel for reuse with the new beam. Then came the crucial operation of cutting the main cables; an acetylene torch was used on the first beam. Although the effect of cutting the cables was undoubtedly transmitted through the adjacent deck in the form of an impact force, no obvious signs of damage was detected in the other beams.