This article examines levels of involvement of weekly church attenders in Catholic parishes in Australia, New Zealand and the United States through an analysis of data from the International Congregational Life Survey. Factor analysis was used to identify four questionnaire items related to parish involvement which were then combined to produce a parish involvement score for each attender. When mean parish involvement scores were plotted against year of birth, the resulting graphs revealed remarkable similarities across all three countries. The graphs showed reasonably constant involvement scores for attenders born before 1955, whereas scores for attenders born between the mid-fifties and the mid-seventies declined as age decreased. Theoretical discussion focuses on the meaning of the variation in scores with age for attenders born after 1955. The article considers whether the results are most likely due to an age effect or a generation effect, and how the answer to that question might have serious implications for the future of Catholic parishes. (Contains 2 tables and 3 figures.)