The effect of monetary policy on long-term interest rates has been a question of interest in recent years. A number of papers, relying on single-equation estimation techniques, have presented evidence that long-term interest rates exhibit sizable and significant responses to unanticipated changes in the Federal Reserve's target federal funds rate. This paper examines these findings in light of conflicting findings from VAR studies, which indicate negligible effects of innovations in the federal funds rate on long-term rates. To address the issue we use a single-equation approach where unanticipated changes in the federal funds rate are measured as residuals from policy reaction functions. We also estimate VAR specifications, which incorporate information about the timing of changes in the Federal Reserve's target federal funds rate. Our single-equation estimates provide evidence of strong responses of long rates to unanticipated changes in the federal funds rate both for the Greenspan period and for a longer period back to the mid-1960s. It seems likely that estimated VARs for the post-1987 years are less successful in isolating monetary policy surprises than was the case for earlier years.