The authors use empirical research into the environmental practices of 31 manufacturing small and medium-sized enterprises (SMEs) to show that 'business performance' and 'regulation' considerations drive behaviour. They suggest that this is inevitable, given the market-based decision-making frames that permeate and dominate the industry in which manufacturing SMEs operate. Since the environment is a pillar of corporate social responsibility (CSR), the findings have important implications for CSR policy, which promotes voluntary actions predicated on a business case. It is argued that this approach will not alter the behaviour of manufacturing SMEs significantly because CSR practice will be regarded as an optional and costly 'extra' affecting core business activity. Consequently, the use and development of existing regulatory structures, providing minimum standards for many activities covered by CSR, remains the most effective means through which the behaviour of manufacturing SMEs will be changed in the short to medium-term. Another feature of the paper is the distinction made between 'business performance' and the 'business case' argument. Business performance emphasises cost reductions and efficiency whereas the business case accentuates the benefits to shareholders of good practices as their firms become more attractive to stakeholders and society. Manufacturing SMEs try to improve business performance because of the pressures placed on them by market-dominated decision-making frames. These frames do not encourage manufacturing SMEs to undertake voluntary actions for the benefit of wider stakeholders and society. © Springer 2006.