This study re-examines the validity of the relationship between the Singapore dollar–U.S. dollar exchange rate and relative prices using the latest econometric methodologies that account for non-linearity. Among others, this study finds Exponential Smooth Transition Autoregressive (ESTAR)-type non-linear mean-reverting adjustment process of the nominal Singapore dollar–U.S. dollar rate towards the consumer price index ratio. Unlike previous findings of a linear cointegration relationship between the nominal Singapore dollar–U.S. dollar exchange rate and consumer price index ratio, this study shows that the relationship is in fact non-linear in nature. The major economic implications of our findings are: (1) policy makers need to take non-linearity into consideration in their policy decisions; (2) the Monetary Authority of Singapore (MAS) is able to maintain the macroeconomic equilibrium despite the authority’s strong dollar policy; and (3) one should keep track of Singapore’s monetary policy and other innovations in aggregate demand in order to closely monitor the movement of the Singapore exchange rate.