We find evidence for asymmetric behaviour in the monetary policy of the Reserve Bank of Australia. From 1984 to 1990, it acted with considerable discretion leading to a relatively poor performance of an interest rate rule. However it behaved asymmetrically with regard to inflation and the output gap in downturns and upturns. On embracing inflation targeting from 1991, it enhanced its credibility by anchoring inflation expectations. Not only did its actions become more predictable from 1991 to 2002, it responded asymmetrically only to the output gap, switching to respond more acutely in downturns. While its asymmetric behaviour could result from asymmetric preferences or a non-linear aggregate supply relation, our results support the former explanation.