Knowledge as an intangible asset is the most fundamental source of economics. However, as with other resources, it needs to be managed and standardized. In one organization, knowledge related to the field of activity is an essential component. This research was conducted to investigate the relationship between knowledge management and the performance of audit firms with the role of mediator of organizational learning. For this purpose, 128 people were selected using the Cochran formula and the questionnaire was used. The statistical population in this study is all auditors working in the audit institutions located in Tehran, which was selected according to specific circumstances. Pearson correlation test was used for data processing and multiple regression was used and SPSS software was used. The average for the performance variables of the audit firms, knowledge management, and organizational learning are 3.30, 3.40, and 3.40, respectively. The related statistical analysis indicated that the knowledge management variable and its five dimensions had a significant effect on the performance of the audit firms. The correlation between knowledge management and performance of the audit firms is 0.39, which indicates a moderate and positive relationship between the two variables. The obtained variance also showed that the knowledge management variable explained 15% of variations in the variance of audit firms performance. Also, in the case of average variables, the results showed that the average of performance variables of the audit firms, knowledge management and organizational learning were higher than the average, and these differences were statistically significant and significant.