This paper develops a long run growth model for a major oil exporting economy and derives conditions under which oil revenues are likely to have a lasting impact. This approach contrasts with the standard literature on the "Dutch disease" and the "resource curse", which primarily focus on short run implications of a temporary resource discovery. Under certain regularity conditions and assuming a Cobb Douglas production function, it is shown that (log) oil exports enter the long run output equation with a coe¢ cient equal to the share of capital. The long run theory is tested using a new quarterly data set on the Iranain economy over the period 1979Q1-2006Q4. Building an error correction speci…cation in real output, real money balances, in ‡ation, real exchange rate, oil exports, and foreign real output, the paper …nds clear evidence for two long run relations: an output equation as predicted by the theory and a standard real money demand equation with in ‡ation acting as a proxy for the (missing) market interest rate. Real output in the long run is shaped by oil exports through their impact on capital accumulation, and the foreign output as the main channel of technological transfer. The results also show a signi…cant negative long run association between in ‡ation and real GDP, which is suggestive of economic ine¢ ciencies. Once the e¤ects of oil exports are taken into account, the estimates support output growth convergence between Iran and the rest of the world. We also …nd that the Iranian economy adjusts quite quickly to the shocks in foreign output and oil exports, which could be partly due to the relatively underdeveloped nature of Iran's …nancial markets.