Cancellation of income and substitution effect implied by King-Plosser-Rebelo (1988) preferences breaks tight coefficient restriction between the slope of the Phillips curve and the elasticity of consumption with respect to real interest rate in a sticky price macro model. This facilitates the estimation of intertemporal elasticity of substitution using full information Bayesian Maximum Likelihood techniques within a structural model. The US data from the period 1984 - 2007 supports low intertemporal elasticity of substitution and strongly rejects a logarithmic and an additively separable utility specification commonly applied in the New Keynesian literature. Keywords: Monetary policy, Bayesian estimation, Non-separable utility. JEL: E32, E52, E21