Serious Leisure has received considerable attention in the leisure research for the past forty years. Building on recent efforts to operationalize serious leisure constructs, this study examined the relationship between serious leisure characteristics and rewards in the context of indoor competition climbing, a sport recognized as a potential serious leisure pursuit. The purposes of the study were to validate the 18-item Serious Leisure Inventory Measure (SLIM) as well as the three-factor model of serious leisure proposed by previous researchers. A national sample of 646 indoor competition climbers completed a 59-item survey. Results suggest partial validation of the 18-Item SLIM and a three factor model of serious leisure characteristics and rewards. Serious leisure characteristics significantly, positively contributed to personal and social rewards in the structural model, confirming the relationships and distinctions between these constructs. Further replication and validation of the 18-Item SLIM with different populations is recommended.