This study assesses the effect of operating cash flow on earnings management of Nigerian Banks. The study adopted Ex post Facto research design. The study used sample of fifteen (15) Nigerian banks from 2010 to 2019. Data for the study was collected from annual reports and accounts of the banks. Regression analysis was used to test the hypothesis with the aid of E-view 9.0. Based on this, the study revealed that operating activities are not statistically significant and have a negative effect on total accruals earnings of Nigerian banks. The study concludes that the importance of risk management activities is aimed at reducing future cash flow. Based on this, the researcher recommended among others that managers should be more likely to opportunistically boost operating cash flows if the firm has a cash flow forecast like engaging in principal financing source for maintaining the operating capability of the entity in terms of repaying loan and making new investment.