The use of a Production Management System is now widely accepted as one of the keys to manufacturing competitiveness. However, the current low level of adoption and successful implementation of such systems in small and medium Irish enterprises remains a pervasive and worrying problem. Following a review of the relevant literature on the introduction of Production Management Systems into Small and Medium Enterprises, intensive case data on fifteen companies and more extensive survey data on a further thirty representative of the main industrial sectors were gathered and analysed. The main barriers to adoption and use of Production Management Systems in Irish SMEs were isolated and examined, and the implications drawn for future research and practice.