The current global economic crisis has affected many countries. However, if there are structural deformations in their monetary and banking systems, the tolls are greater. Sudan banking system suffers those deformations. Most developing countries suffer from low levels of income in addition to the low savings that are result from the lack of sophisticated savings channels. Hence, investments depend on the individuals' abilities on savings where they are major motivating vehicle for economic activity due to its direct correlation with capital accumulation process that increases the productive capacity for the national economy and help to create job opportunities and achieving economic development. Subsequently, the importance of the investment comes from the effective role that can be practiced on the national product. Currently, Sudan endures severe economic crisis which the degeneration of its economic sectors, subsequent deteriorating productivity and diminishing revenues specially after the secession of the Southern region and loss of more than 75% of oil resources. The needs for investments escalate to revive its ability to survive, without that can be mission impossible. There is need to explain the impact of influencing factors on the investment function in the Sudan. Channeling money needs banking systems to facilitate that job. Sudan as an example of LDCs the banking sector has been suffering from the problem of cash outflow over the last three decades, generating the following impacts: Loss of banking sector of its role of financial intermediation, cash scarcity in the banking sector, large government borrowings from unreal source of finance, thus, more inflation. The book specify the main determinants of cash outflow from the banking sector in Sudan. Hence, those revealing the major impacts of the cash outflow on the economic activity and rates of inflation. The research hypotheses were: the Banks economic behavior of attainment reserves and expanding loans is main cause of cash outflow, the government financial activity to cover its budget deficits, and the effective demand for money liquidity by the public are the main factors transmitting the impacts of cash outflow to the major macroeconomic variables e.g., Money stock, aggregate demand and supply, cost of resource adjustment, and the rate of inflation. Monetization of bank loans via allowing the growth in the effective demand for liquidity by the public directly leads to aggravation of inflation given the downward trend of money velocity, Monetization of bank loans via financing the current deficits of the government, causes inflationary pressures due to aggregate demand expansion, the real side of the economy will not be affected.