This study aimed to identify and model the causal and interfering conditions against corruption by auditing firms. This research is applied objectively and it is among the studies with mixed methods. In the qualitative section, interviews were used to collect data and concepts and categories were identified using Grounded theory. In the qualitative section, the required information was collected using a researcher-made questionnaire. The statistical sample of the research consisted of 15 people in the qualitative section who were selected by snowball sampling method and 302 senior students and PhD students in accounting and auditing were selected in the quantitative section by random sampling method. SPSS24 and LISSREL software were used for data analysis. Based on the results of the qualitative section, the interferer conditions include the disadvantages of information disclosure (4 concepts), special organizational considerations (2 concepts) and political failure (3 concepts) and six categories of essential information (5 concepts), participation (3 concepts), accountability (2 concepts), secrecy (4 concepts), corruption (2 concepts) and social responsibility (3 concepts) were identified as causal conditions of corruption in this study. The results of confirmatory factor analysis in the quantitative section confirmed the results obtained in the qualitative section.