The modernisation of production and the growth of output in the agricultural sector in Ireland, as in many other countries, have been associated with the adoption of many innovations which have contributed to a very significant decline in labour inputs and its replacement by mechanisation. In farming the process of mechanisation can be understood as the adoption of production methods in which human labour and draught animals are replaced to a high degree by technology which can result in greater productivity of both agricultural labour and land. It is part of a wider range of processes which result in a significant level of structural adjustment in the organisation of the total economy. Mechanisation facilitates this adjustment and enables the fewer remaining farmers to achieve higher income levels and an improved standard of living. However, farmers vary in their ability to respond to the requirements of this process for a variety of reasons including economic constraints, demographic factors and in some instances locational disadvantages. The differential impacts of these factors between fanners introduces significant temporal and spatial dimensions into the adoption and diffusion of mechanisation. While there have been many studies of the spatial structure of agricultural production in Ireland (Stamp, 1931; Gillmor, 1977, 1987; Homer et al., 1984; Walsh, 1991) and of the sources of variation in growth rates (Conway, 1975; Cuddy, 1982; Boyle, 1987), there has been surprisingly little systematic analysis of the influences on the adoption and diffusion of innovations in Irish agriculture.