The purpose of this study is to investigate the relationship between social capital and mental well-being with the organizational ability of employees of the Social Security Organization of Bojnourd. The research is descriptive-survey in terms of applied purpose and in terms of the type of research and implementation method. The statistical population included all employees of Bojnourd Social Security Organization in the number of 120 people and the sample was selected based on Morgan table 92 people by simple random sampling method. Data were collected by Nahapit and Gushal (1998) Social Capital Questionnaire, Mental Welfare and Organizational Capability of Jamshidi Kolshtajani (2014). Cronbach was estimated (0.94), (0.95) and (0.96), respectively. To analyze the data in the descriptive statistics section (mean, standard deviation and calculation of central indicators and dispersion) and in the inferential statistics section to measure the relationships between variables, Pearson correlation coefficient and regression were used by SPSS21 statistical software. The results showed that there is a relationship between social capital and mental well-being with the organizational ability of the employees of the Social Security Organization of Bojnourd (r = 0.984). In general, the variables of social capital and mental well-being were able to explain (9.68) percent of the variance of the organizational capability equation. It can be concluded that the development of social capital and mental well-being in the social security organization can be an important step towards improving organizational capability. Managers at Social Security have a positive view of helping employees do better by providing mental well-being to demonstrate their abilities.