Case study based literature on relationship development presents in-depth information on contextual factors in relationship development. However, little quantitative evidence is available about key aspects of buyer-supplier relationships in each stage of its development, such as the level of trust/commitment, buyer’s and supplier’s dependence. The study will try to fill this gap by identifying and quantifying these aspects from the buyer’s perspective in each development stage. A comprehensive survey among 238 Dutch purchasing professionals provides evidence on how these characteristics of relationships changewhen relationships develop over time. The results largely confirm the hypotheses, which stem from the extant literature about organizational dependence and trust/commitment. A notable finding is that the buyer perceives to be dependent on the supplier, even in a desirable relationship. Managerial implications are that: (1) industrial marketers should be aware that professional purchasers feel dominated by them, even in relationships that are positively evaluated and therefore desirable in the view of the buyer; and (2) that purchasers should be aware that dependence implies vulnerability, even when the relationship is still developing in an otherwise desirable way.