Effective knowledge sharing as one of the basic aspects of knowledge management can be considered as one of the most important successes in changing and complicated contexts of sport organizations. The aim of this study was to study the effects of intrinsic and extrinsic motivations on knowledge sharing in employees of physical education organizations of Isfahan. The research method used descriptive – survey and a practical approach. A standard questionnaire (Lin, 2007 and Kou and Young, 2008) was used to collect data. The validity of the questionnaire was determined using viewpoints of organizational behavior experts and reliability was determined as Chronbach’s alpha=0.86 for all variables. The research population consisted of all employees of physical education organizations in Isfahan. The sample (n=150) was randomly selected through multistage cluster sampling method. Conceptual framework of this study was a progressed model of reasoned action theory. To measure the validity of the model, structural equation modeling was applied. Path analysis results verified the relationship of variables. AMOS18 and SPSS18 softwares were used for data analysis. The results of this study showed that the expected organizational rewards, reciprocal benefits, knowledge self – efficacy, and enjoyment of helping others influenced attitude towards knowledge sharing in employees of Isfahan physical education organizations.