In spite of the strengthening regulation of ethical conduct and numerous studies in relation with auditors, some factors can affect them in ethical dilemma situation. This study attempted to find the most important terms in dealing with auditor's judgment. The researches on the past studies documented that the most scandals on auditing irregularities was happened because of auditors' unethical behaviors. In addition, previous studies are showed that the understanding of ethical code of conduct and also audit standards is related to make decision by auditors. Consequently, ethics was founded as one important significant factor in process of auditor's judgment on financial statements. The main objective of this research is to investigate the effects of ethics and the code of conduct on auditor's judgments on material misstatements into financial statements. Data are collected from 321 mangers, partners and authoritative auditors among Iranian audit firms. The results of SEM indicate amazing ranking of ethics and code of conduct among Iranian auditors and they significantly affect judgment of these respondents.