This research aims to examine the mediating role of the cash conversion cycle (CCC) in shaping the influence of conservatism policy on investment decisions. This applied study was conducted on Non-Financial Firms Listed on the Egypt Stock Exchange, EGX 100 during the period from 2003 to 2022. The study depended on secondary data published in the financial statements and reports of these companies. In addition, it also relied on the data method that combines time series data with cross-sectional series data (Data Panel) to conduct the study, and the data were analyzed statistically by relying on statistical software packages STATA 14. The study results showed a significant negative impact of conservatism policy that is represented by accounting conservatism (AC), on investment decisions. Accounting conservatism also has a negative impact on the cash conversion cycle, while there is a positive impact of the cash conversion cycle on investment decisions. The mediated effect of the cash conversion cycle is about 0.3 times as large as the direct effect of accounting conservatism on investment decision.