The presentation will cover two themes. First, a presentation of “the Religions in Finland Project”. This involves a database where we have collected data since 2006 on religious organisations that operate in Finland. Second, a presentation of the results of a recent project in which we used the data in the database to form indices of local religious diversity. The indices were used as variables in the analysis of local surveys which aimed to examine the impact of local religious diversity to people's religiosity and religious attitudes. In this way, the presentation aims to raise discussion on the methods and value of collecting organisational level data on religious and spiritual groups.