The dark side of buyer–seller relationships may be treated as an under investigated field of research. Themain objective of this paperwas to explore the negative consequences of being involved in deep supplier relationships. The data gathered from 92 in-depth interviews with purchasing managers were used for the qualitative data analysis. The negative relationship consequences identified in the study were assigned to six categories: supplierspecific forces, buyer-specific forces, relationship-specific forces, product-specific forces, network-specific forces and environment-specific forces. The study extends our knowledge about the negative consequences of deep supplier relationships in Eastern Europe by illustrating the complexity of the factors involved and the complex interactions that influence the context. An exploratory approach was taken which means that findings cannot be generalized to other contexts. However, this creates an avenue for further research.