The availability of secure energy resources at sustainable quantities and affordable prices is fundamental to South Africa’s current objective of enhancing and sustaining its current growth trajectory. Economic reforms, since the early 1990s, have led to the economy growing at an average rate of almost 5% per annum. A major consequence of this strong growth is the rapid increase in domestic demand for oil energy. With small amounts of proven oil reserves, the rise in oil demand as an essential energy source has prompted an increasing reliance on external sources for domestic crude oil supplies. High oil prices, the extent of proven oil reserves, instability in major oil producing regions and the rise in ‘oilnationalism’ have raised serious concerns about the security of South Africa’s oil supplies. In this context, a comprehensive understanding of oil import security risks is critical as it will guide in the formulation of energy policy framework aimed at alleviating the impact of oil import risks. This study utilises portfolio theory to provide quantitative measures of systematic and specific risks of South Africa’s crude oil imports over the period 1994 to 2007. It explains the relationship between supply sources diversification and oil energy security risks, and highlights the impact of different crude oil import policy adjustment strategies on the total crude oil import risk for South Africa. The results for the adjustment strategies show that: (a) a policy of having the same quantity of oil imported every month or a constant quantity of oil imported from the supply regions reduces both systematic and specific risks of oil import portfolio, and (b) a reduction in specific risks of South Africa’s oil imports can be achieved if some of the Middle Eastern supplies can be diversified to less risk regions of Europe, North America and Russia.