This paper uses the example of a participatory design project in support of urban planning to analyse the complexity of design decisions. A set of design decisions is described and discussed, showing who made decisions on what. We discuss big decisions and small decisions, decisions internal to the project and related to the outside world, and decisions that might be called non-decisions. A conceptual framework on power is applied for understanding decision-making, power and conflict in Participatory Design projects. We discuss the concept of power, making distinctions between sources of power (among them expert knowledge, resource allocation, values, and interpretations); as well as between various mechanisms guiding decision-making: power, influence, trust and seeking understanding.