Shared governance is an approach to empowering nurses and other health care workers to have authority for decisions concerning their practice. Commonly, visible definers of shared governance are groups of workers known as 'councils' whose membership works collectively to realise a shared goal. The literature is replete with rhetoric as to the benefits of shared governance yet the evidence base concerning shared governance and especially decision-making within shared governance is scant. This paper presents a case study of group decision-making within a UK shared governance council model. The evidence which informs the case study is drawn from a doctoral action-research study to strengthen decision-making within the model. Eight key factors affecting decision-making and four supportive conditions are presented and incorporated into a conceptual model. Within the case study, presence of these factors was found to be necessary but not sufficient to enhance decision-making. Factors included having a clear issue, clear aim, fitting issue, manageable issue, size, lead person allocated, level of authority, background information, key informant/s, a mechanism for evaluation, adequately skilled members, support/guidance and sufficient/appropriate membership. Aspects of group decision-making processes are highlighted and compared with established management, shared governance and group dynamics theory.