Purpose: Second Life is a user-created online virtual world, which is a place where people with shared interests can meet and be together and share information. The purpose of this study is to investigate whether Second Life communities foster and nurture social capital, whether social capital within Second Life is related to social capital outside the virtual world, whether some characteristics affect the likelihood of users having social capital, and whether some existing measure of social capital can be modified and used to study social capital in Second Life. Design/methodology/approach: Study is based on a statistical analysis of data gathered in a web survey of a convenience sample (N=67) of Second Life residents. The social capital measure used was based on Bullen and Onyx, 1998. Findings: Second Life is an environment that fosters the emergence of social capital. Residents, who consider themselves as producers, have higher levels of social capital than those, who consider themselves as non-producers. Having social capital within Second Life is unrelated to having social capital outside the virtual world. Consistency of the instrument proved to be excellent for measuring social capital within Second Life and good outside the virtual world. Research limitations/implications: Small sample size and the composition of the research population limit the possibilities to generalise the findings. Practical implications: Second Life is a potent environment for community building and collective action. Communities and collective action within Second Life cannot be based, however, on the social activity outside the virtual world. Originality/value: The present study is the first systematic investigation of social capital in Second Life.