UHPFRC (Ultra High Performance Fiber Reinforced Cementitious Composite), complemented by reinforcement steel bars, is used for the rehabilitation and strengthening of existing bridges by adding a layer of UHPFRC, often on top of the bridge deck slab in reinforced concrete. Basic principles of the method and recent project realizations in Switzerland are presented. The underlying design concepts and issues of dimensioning and detailing are introduced, and main experiences in casting UHPFRC onsite are mentioned by means of three recent application examples. UHPFRC interventions are cost effective and contribute in lowering the environmental impact because existing concrete structures are preserved and remain in service, rather than demolished and replaced. The service duration of bridges is thus extended significantly while responding to the demand of future use of bridges. The UHPFRC Technology allows to improve sustainability of bridges.