This paper tries to infer and compare the evolution of the Federal Reserve’s (unobserved) inflation target series by estimating a monetary model under the alternative assumptions of rational expectations or subjective expectations and learning. In the estimated model that assumes that economic agents have rational expectations, the implied inflation target displays large shifts over time: it starts at 2% in the early 1960s, it rises to 8% in the 1970s, and it falls to 4% and 2% in the 1980s and 1990s. When the assumption of rational expectations is relaxed in favor of learning by the policymaker, the inferred target is, instead, remarkably stable over time. The target assumes values between 2% and 3% over the whole postwar sample. The findings suggest changing beliefs and learning by the Federal Reserve as major endogenous causes of the perceived variation in the inflation target. When the model is allowed to take the central bank’s evolving beliefs into account, the joint evolution of US inflation, output, and monetary policy decisions can be explained without requiring large exogenous changes in the inflation target.