This work examined the optimality of the inclusion of the exchange rate in the reaction function of the Central Bank in an inflation targeting framework. The study attempts to answer the question whether the exchange rate should have an independent role in an open economy Taylor-type rule. To this end, a Taylor-type rule is incorporating the exchange rate is estimated by the cointegration and vector error correction modeling (VECM) using quarterly data for the period of 1995 to 2009. The empirical studies point out the importance of the exchange rates in explaining and forecasting the behaviour of the South African Reserve Bank monetary policy control variable.