In 2001, more than 1.2 million worshipers in over 12,000 congregations in four countries participated in the International Congregational Life Survey (ICLS). The ICLS was an expansion and revision of previous surveys conducted in Australia (the National Church Life Survey) to include congregations and worshipers in New Zealand, England and the United States. Researchers in the four countries collaborated in the design and implementation of the survey with the aim of providing mission resources for congregations and parishes. Survey results were used to produce customized reports for each participating congregation showing worshipers' responses in comparison to the respective national average. These reports were designed to help congregations identify their strengths and become stronger in mission and ministry. This article presents an overview of the methodology used for inviting congregations in each country, summarizes response rates and provides a basic international comparison of worshipers. Comparisons reveal commonalities across the four countries and highlight areas of difference. This overview sets the stage for theoretical articles comprising the remainder of the Special Issue. (Contains 3 tables.)