Using a sample of 11,365 unique US firms over the period 1966 to 2021, this study examines the relationship between the age of a firm and its cash holdings. We categorize firms as young, mature, or old based on their age or years of operation. Our results show that firm age is one of the important determinants of cash holdings and that managers adjust cash holdings in response to changing financial needs and risks as firms age. We find that young firms tend to hold higher levels of cash than more established firms and that the marginal value of cash holdings is higher for younger firms. This is consistent with the notion that young firms are more focused on growth and investment and may have limited access to external financial resources. In contrast, mature and old firms tend to hold lower cash levels, possibly due to greater financial stability, increased creditworthiness, and a lower need to manage financial risks. Controlling for significant variables, we confirm our findings with the robustness tests. Taking care of the endogeneity issue, we still can confirm that firm age is negatively significant to the level and the marginal value of cash holdings.