Existing reinforced concrete (RC) andmasonry structures (particularly buildings and bridges) may be affected by significant deterioration and often need to be upgraded mainly to stop and/or delay material deterioration or to meet the new mandatory seismic design requirements. Applications of advanced materials for retrofitting and upgrading existing structures have been rapidly grown in past years because of their several advantages with respect to traditional strengthening systems. In the case of buildings, seismic upgrading performed as prevention measure needs to meet the strict requirement of avoiding people to leave and so being compatible with the daily functions during works execution: therefore, this crucial aspect has to control the conceptual design of retrofit interventions. These remarks have introduced new challenges in the development of novel advanced materials-based strengthening solutions for the seismic upgrading of deficient existing buildings that can be applied wholly from the exterior of the building. The experimental validation of such solutions and the relevant calibration of reliable design formulations for future seismic risk mitigation strategies is the main focus of this work. This paper outlines the basic principles of advanced materials-based seismic upgrading strategies on existing RC and masonry structures in order to avoid the most common brittle and premature failure modes. An overview of different experimental investigations carried out over the last two decades at the Department of Structures for Engineering and Architecture of University of Naples Federico II is presented. The experimental programs confirmed the effectiveness of such fast and low impact methodologies for the definition of design-oriented procedures for retrofit solutions based on advanced composite materials.