Social capital results from shaping and establishment of values, norms, traditions, conventions and rules in self realization manner and in the context of social interactions and it produces hypothesis in different fields such as empathy, cooperation, humanism, loyalty and conscience in people’s social lives. The relationship between social capital and citizenship behavior is explored in this paper. The population (239 employees) includes all employees of Welfare Organization of North Khorasan in (2012) including officially employed, employed by contract, and other forms of employment. Sampling was performed randomly based on different fitted classifications and 142 employees were selected out of the population. The method of the study is descriptive with correlation. Data is collected using two questionnaires: Social Capital Questionnaire and Standard Organizational Citizenship Behavior Questionnaire (Organ and Farh). Data was analyzed using Pearson Correlation Coefficient and Mono Lateral Variance Analysis. The data analysis was performed in descriptive and inferential levels. The results show that there is a relationship between social capital and organizational citizenship behavior and all parameters of social capital (hierarchy, togetherness, trust, interpersonal relations and social cohesion) are directly related with organizational citizenship behavior. In addition, the result of Mono Lateral Variance Analysis shows that organizational citizenship behavior is not significantly related with employment type, experience, age group and gender and it is only related with education level.