Blending of two or more different fibre types is of crucial significance to the textile industry. Shore [1] reports that several interrelated factors may contribute to the decision to replace a homogeneous textile material by a blend: Economy: The dilution of an expensive fibre by blending with a cheaper one. Durability: The incorporation of a more durable component to extend the useful life of a less durable fibre. Physical properties: A compromise to take advantage of desirable performance characteristics contributed by both fibre components. Colour: The ability to develop novel designs incorporating multi-colour effects. Appearance: The attainment of attractive appearance and tactile qualities using combinations of yarns with, for example, different lustre. The blend of cotton with polyester represents one of the most important textile substrates, being widely used as a fabric for shirring. The synthetic fibre enhances the crease resistance, dimensional stability and easy-care properties of the blend, and the cotton component contributes contort, especially important for products worn next to the skin. In spite of the rapid growth in the use of synthetic fibres, natural fibre blends of, especially, cotton and wool have been of some importance over many years' Inclusion of wool in cotton products enhances properties such as appearance retention, bulk and comfort. Rocklea Spinning Mills has recently launched Colana yarns, manufactured from 70% cotton and 30% wool. CSIRO Textile and Fibre Technology has provided scientific and technical support to Rocklea for this project, with funding provided by CSIRO, The Woolmark Company, and more recently, the Australian Cotton Cooperative Research Centre (Cotton CRC). This paper focuses attention on blends of cotton and wool, drawing on past and present experiences in the Colana initiative.