The use of fibre composites, formed from high modulus carbon, glass or aramid fibres combined with suitable resins and adhesives, for strengthening concrete structures is growing rapidly. This paper summarises The Concrete Society Technical Report 55, Design Guidance for Strengthening Concrete Structures Using Fibre Composite Materials, which is the first document to give design guidance in accordance with British codes. The report also describes some of the systems that are available and summarises the properties of the various materials. Typical applications are described along with the requirements for quality control both of the materials and the site operations.