Purpose-By expanding the technology acceptance model, the purpose of this paper is to provide a research model to examine the impact of online (information quality, system quality and service quality) and offline (offline activities) features on the sustainability of virtual communities. Design/methodology/approach-Based on a survey of 165 community members, the paper uses structural equation modeling approach to investigate the research model. Findings-The findings indicate that perceived of usefulness, perceived ease of use and offline activities are determinants of sustainability of virtual communities. In addition, information quality affects perceived usefulness, while system-quality and service quality influence both perceived ease of use and perceived usefulness of virtual communities. Research limitations/implications-Since this study only considered non-profit virtual communities, it is unclear whether these analytical results can be generalized to other virtual communities. Further research can apply this research model to examine profit-oriented virtual communities, such as eBay.com.tw or brand communities. Practical implications-To sustain a successful virtual community, attention must be paid to enhance both online and offline interactions, including content management, specific sets of web site functions and offline communication. Virtual community providers can apply the findings of this study to focus on the determinants of success for their virtual communities. Originality/value-Theoretically, while drawing upon the extended TAM, this paper provides a model that is capable of understanding the determinants of sustainability of virtual communities. From a managerial perspective, the findings should provide further insight into member behaviors, leading to more effective strategies for expanding the virtual community.