The flexl.bility to change product and processes quickly and economically represents a significant competitive advantage to manufacturing organisations. The rapid rise in global sourcing, has resulted in manufacturers having to offer greater levels of customisation, thus a wider product range is essential to an organisation's competitiveness. The rate at which new products are introduced to the market has also increased, with greatly reduced development times being essential to a new product's market success. Hence there is a strong need to have a flexible manufacturing system such that new products may be introduced rapidly. These drivers have made the need for flexibility within manufacturing systems of great importance. However, there are many types of flexibility and to ensure that organisations correctly target these types of flexibility there is a need to measure fleXlbility, because, measuring fleXlDility allows manufacturers to identify systems which will improve their performance. This research, therefore, has focused on the development measures for two types of flexibility ie. mix fleXlDility and product flexibility. These represent the ability to change between the manufacture of current products i. e. mix flexibility and the ability to introduce new products i.e. product fleXlDility. In order to develop effective measures for these types of fleXlbility a conceptual model has been developed, which represents the current and potential future product range of manufacturing systems. The methodology developed for measuring mix and product flexibility has been successfully applied in two companies. These companies represent diverse manufacturing environments. One operates in high volume chemical manufacture and the other in low to medium volume furniture manufacture. Through applying this methodology in these two companies it has been demonstrated that the methodology is generic and can be used in a wide range of companIes.