The value in a firm's relationships needs to be developed and managed carefully and marketing managers need to be able to quantify this value in order to manage it and in order to argue for their share of the firm’s resources to develop it. This paper describes a study that aims to test a hypothesised model of the intangible part of the value that is manifested in buyer-seller relationships and a set of scales to measure it. The focus of the research, which synthesises a framework from the intellectual capital literature, is on business to business situations and on the value of the relationship to the seller, rather than to the buyer. In the study described, data from a survey of relevant managers were analysed using confirmatory factor analysis and structural equation modelling techniques to test the hypotheses.