The heritage of modern architecture in Colombia is continuously being modified and destructed. The interventions and affectations, such as demolitions and transformations, of a selection of important buildings, urban ensemblesand neighborhoods dating from the 1930s to the 1960s in Bogotá and four of its neighboring provinces were registeredand described. Through two research projects the proportions of the loss of buildings and –worse– the loss ofthe modern traditions were partially illustrated, although some well-conserved designs were found also.