Managers in commercial sport clubs must develop efficient marketing programs for their target market. This necessitates the managers to collect and analyze the information about the behavior of program participants, i. e. consumer behavior. This paper is intended to examine consumer preferences among sport participants. A case study approach was taken to focus upon choice decision process among commercial sport club users. Analyses were made to investigate club users' trade-offs between sets of service attributes. Conjoint analysis was applied in this process. Conjoint models represent a decompositional approach for predicting individunl's preferences for the stimulus object as a whole. The data for this study were collected in urban commercical sport clubs located in Osaka. A sample of 198 club members were studied through computer interactive interviewing. Six service attributes and 18 levels were considered in the study design. Service profiles which were combinations of the attributes and levels were presented to respondents by means of paired comparisons. The overall ranked data were analyzed using Johnson's nonmetric tradeoff algorithm. The use of conjoint analysis allows the researcher to determine consumer's part-worth utilities for each service attribute under study. In addition, consumers are segmented on the basis of attribute importance in order to enhance the analysis. The findings of the case study include : distance and augmented facilities were more influencial factors to users' preferences than membership fee and instructor quality. Membership initiation fee and business hour were not very important. The results of segmentation suggest that `distance' segment and `augmented facilities' segment represent relatively large subsets of the club user market. It can be concluded, from what has been found in the study, that conjoint analysis is a powerful and useful technique for analyzing consumer preferences in the commercial sport club maket.