Purpose - The purpose of this study is to establish a theoretical basis for evaluating a strategic increase in customers' perceptions of service/product quality - specifically in terms of an increase in relationship quality and customer loyalty in a B2B environment - and to test this theoretical basis empirically. Design/methodology/approach - Drawing on the relationship-marketing literature, the authors empirically test a model of business loyalty in a sample of 234 advertising agencies' clients. Findings - Using the Grönroos conceptualisation, a clear pattern of service-quality dimensions is established and several important findings are reported - including empirical verification of the mediating role of overall relationship satisfaction in the formation of loyalty attributes. The effects of trust and commitment are also verified. Research limitations/implications - Studies that model attitudinal as well as behavioural relationship outcomes have strong precedence in the relationship marketing area. Although in this study the "intentions" approach is followed rather than a behavioural one, the measurement of the real behaviour of industrial clients proves to be very difficult from a practical point-of-view. Practical implications - In this service continuum, managers need to clearly define relationship development strategies, service provision policies and develop homogeneous service provision. Towards this direction, it is essential that firms communicate the service and product quality standards to partners so that differences in service provision can be avoided. Originality/value - The study integrates the concepts of service/product quality, relationship satisfaction, trust, and commitment in a business-loyalty model, demonstrating the benefits of investing in relationships based on trust and commitment. © Emerald Group Publishing Limited.