Community information systems have the power to transform communities. However, without fully understanding the pre-requisite factors affecting community information system viability, and the complex relationships between these factors, communities struggle to manage such projects in a way that leads to viable systems that deliver real benefits. This paper develops and presents a Model of Community Information System Viability Pre-requisite Factors, based on both existing literature and the study of three community information system projects. This Model represents the generic factors that inform viability (i.e. leadership, active membership, funding, awareness, and system design and functionality), and also considers the impact of community context. This study argues that the viability of a Community Information System cannot be considered in isolation. All factors are directly impacted by the value of the Community Information System to the community. Management can also heavily impact on the success of a Community Information System.