This study examined whether or not financial intermediation can explain the variations in the savings-investment ratio in South Africa during the period 1990 to 2012. The study specifically tests the McKinnon Conduit Effect hypothesis which states that increasing interest rate raises the capacity of financial savings via financial intermediaries based on data from South Africa. Apart from informal graphical test, this study employed formal tests such as the Augmented Dickey-Fuller and Phillips Perron stationarity tests to test the properties of the variables considered, including interest rates, for stationarity. In order to ascertain the long-run and short-run dynamics between its variables, the Johansen co-integration test is utilized, while the Error Correction Mechanism is also employed. Results from the study state that financial assets (a proxy for financial intermediation), income and real interest rate all positively impact the savings-investment ratio. Additionally, short-run analysis results showed that income, financial assets and real interest rates positively influence the savings-investment ratio. Real interest rates were seen as being both positive and statistically significant. Therefore the study recommended that the financial services sector and the South African Reserve Bank (SARB) should work together as this will result in the improvement of efficiencies in price discovery with regards to bank charges, access to banking facilities and the timely provision of services in order to encourage savings (for investment purposes) in the South African economy.