The rise of an ostensibly customer-centred corporate culture in the 1980s recognised the importance of "knowing the customer". As a result, customer information systems and associated practices of marketing, customer segmentation, and customer accounting have become significant elements in corporate customer-focus strategies. This paper discusses a range of ethical considerations that flow from the use of customer information systems and critically examines these systems in their organisational and social context. It is well-recognised that customer information systems give rise to concerns of privacy, but this paper raises perhaps more important ethical issues that relate to organisational transformation and significant links to issues of access, equity, alienation, and social exclusion.