The 400 fastest-growing churches (based on the percentage change in average worship attendance in the previous five years) in the Presbyterian Church (USA), a mainline Protestant denomination, were invited to take part in the US Congregational Life Survey. Completed surveys were received from 19,033 worshipers in 93 fast-growing churches. These fast-growing churches were compared to a random sample of 523 PC(USA) churches that also took part in the survey to examine factors related to church growth. Results reveal that measures based on the input of worshipers in each church significantly distinguish between the two groups. Churches are more likely to be growing churches when: (1) larger percentages of worshipers are growing spiritually; (2) the percentage of worshipers who started attending in the previous five years is larger; and (3) larger percentages of worshipers see their leaders as empowering. In addition, churches that were larger five years before the survey were more likely to have grown in the intervening years. (Contains 2 tables.)