Season ticket holders (STHs) are vital to professional sport club revenue and are purported to be the most loyal and involved of fans. Nonrenewal (churn) rates among STHs, however, often exceed 20%. Low member satisfaction, poor on-field performance and low game attendance have all been posited as explanations of high churn rates, but rarely empirically examined. The research reported here employed a unique study of over 4,500 STHs, incorporating both survey research and measures of actual behavior, to determine which variables best explain and predict churn within two professional sport teams. A variety of analytical techniques all suggest that the key variables predicting churn are length of relationship and the number of games attended. New, low attending STHs are over five times more likely to churn than long-term, frequent attendees. Typical management practice is to run reward schemes designed to increase attendance and encourage renewal. The results of this study suggest that fundamental differences in the way new, low attending members evaluate the season ticket product may render those schemes ineffective. Shifting the focus of these STHs toward the intangibles of the product, such as stronger feelings of involvement, a sense of community and increased patron worth, could be more effective at reducing churn.