For decades, auditors have reported their opinions on the financial statements in a typical form in the audit report, however, stakeholders expect more information from auditors, the limited transparency of the actual auditor's activities has led to a dissatisfaction with the performance of the auditors (Brouwer et al. al., 2016). Recent years the auditors' report form has developed, an example of this is the auditor’s disclosure in his report about the so-called key audit matters which the auditor disclose in his professional opinion. This key audit mattersare the most important in the audit of the financial statements for the current period ( Gold and Heilman, 2019) .The new expanded auditor's report seeks to meet the needs of stakeholders for information, as several amendments have been made to the traditional audit report, one of these amendments relates to adding a paragraph on key audit matters or issues that provide new insights to users of financial statements related to important estimates and risks related to the financial statements (Brouwer et al., 2016). In contrast to the above, Li (2017) indicated that the disclosure of additional information by auditors in China has very limited effects compared to the content and form of the key audit matters for foreign countries. The results of the study did not support the idea that the disclosure of the key audit matters achieves High benefits for users of financial statements. Although a large number of previous studies are interested in examining the relationship between disclosure of key audit matters and information asymmetry, and the audit report lag.It can be noticed that most of these studies were conducted on participants and data related to foreign environments (Badawi, 2018; Altawalbeh and Alhajaya, 2019). There is no doubt that this raises a question about the possibility of generalizing the results obtained on the Arab environment? Therefore, the current study seeks to test the effect of disclosure of key audit matters (KAMs) in the audit report of companies listed on the Saudi stock market on the lack of uniformity of information, and the audit report lag.Furthermore, the current study seeks to contribute to narrowing the literature gap related to evaluating the effects of disclosure on key audit matters. In the audit report, which became mandatory for companies listed on the Saudi stock market as of the beginning of 2017.