People can be motivated in numerous ways. Researchers state that motivation is "a process through which a person makes use of available resources, time, talent, and energy, and distributes them in a way they choose". This study presents an interpretive result that has been made in the investigation of the baseball participants` and spectators` motivations those affect participating and spectating at the baseball games. In addition to the investigation their motivations to participate and spectate at the baseball game, this study also examines the relationships among their motivations. Survey methodology was employed to distribute the questionnaire to 437 participants. Group A who only watched baseball games consisted of 211 spectators. Group B who both participated and watched baseball games consisted of 226 participants. The survey questionnaire for this study was translated from English to Korean versions by three experts who were bilingual in both languages. Data analyses for this study included a confirmatory factor analysis for testing the validity of the motivation items, a Cronbach`s α for evaluating the internal consistency of the motivation construct, a multiple regression analysis for investigating the relationships between motivations, commitment, and involvement, and a MANOVA for revealing motivation differences between baseball participants and spectators. Results indicate that there are important research findings in this study. First, with respect to the comparisons of differences between motivation constructs and game attendance levels, all five motivation constructs were defined as factors that positively influenced game attendance. Among five constructs, Stress Reduction accounted for the most significant amount of variance in attendance. Second, there are group differences between baseball spectators and participants in terms of their spectator and participant motivations. The research result indicates that all motivation constructs(Self Actualization, Stress Reduction, Aggression, and Affiliation) except for one construct(Skill Mastery) are statistically significant between groups. The research founds evidences of differences between baseball spectators and participants in terms of their motivations that affected their sport related behaviors. It is recommended that future research investigate motivations with more research participants as well as differences among different sports in terms of inspecting motivations affecting sport consumer behaviors.