An examination of how cash flow influences the investment decision-making process of quoted small and medium-scale firms in Nigeria inspired this study. Operating cash flow, cash flow from financing operations, and cash flow from investing activities were used to simulate portfolio investment and real investment. The data was gathered from the financial statements of manufacturing enterprises from 2015 to 2024. Panel data was analyzed using the ordinary least squares approach. According to the first model, the cash flow of the cited SMEs accounted for 61.7% of the variance in their portfolio investments. There is a positive but insignificant relationship between operating cash flow and portfolio investment for the cited SMEs, and a negative but insignificant relationship between cash flow from investment and financing operations and portfolio investment. Cash flow described, according to Model 2. There is a 64% range in the real investment of the cited SMEs; operational cash flow has a positive and statistically significant effect on real investment, cash flow from investment activities has a negative and statistically insignificant effect, and financing cash flow has a negative and statistically insignificant effect on real investment. The research found that listed small and medium-sized businesses in Nigeria base their investment decisions on cash flow. To improve the investment decision-making process for publicly traded companies, it is recommended that operating cash flows be regulated and monitored. To do this, regulatory organizations like the Nigeria Exchange Group should implement standardized reporting standards. Investment policies should encourage long-term, profitable endeavors, and management should work to develop policies that boost investment cash flows. Firms can make better strategic decisions about allocating capital with the help of government subsidies, tax reliefs, or matching funds, as well as market recommendations for long-term investment planning.