The quality of auditors' professional judgment, as one of the main pillars of audit quality, plays a decisive role in the credibility of financial reports and increasing public trust in financial information. However, these judgments are influenced by several factors, including cognitive abilities, environmental pressures, quality-reducing behaviors, and possible biases. Therefore, the present study, which is an applied and descriptive study in terms of cognition, has been conducted. To collect information, a standard questionnaire was used, which was distributed and collected among 390 auditors working in audit organizations and private sector institutions that were randomly selected in 1403. The structural equation modeling method and SmartPLS software were used to test the hypotheses. The results of the hypothesis test show that cognitive information processing ability has a positive and significant effect on the quality of auditor's professional judgment. Behaviors that reduce audit quality have a negative and significant effect on the quality of auditor's professional judgment. Also, behaviors that reduce audit quality play a partial mediating role in the effect of cognitive information processing ability on the quality of auditor's professional judgment. The findings of this study can help auditing standards setting institutions develop more effective guidelines to improve the quality of professional judgment by optimizing cognitive information processing ability and reducing behaviors that weaken audit quality