The empirically documented regularity that disinflationary shocks are associated with larger output changes than are positive shocks presents an interesting puzzle to macroeconomists. This paper presents, and empirically supports, a new explanation for this asymmetry. The authors show, using a TARCH model, that negative inflationary shocks result in greater inflation uncertainty than positive shocks. As Friedman {1977) argues, and a body of empirical evidence demonstrates, inflation uncertainty leads to lower output growth. Drawing on this explanation, this essay points to an avenue by which the output asymmetry of inflationary shocks can be explained. (JEL E30, E31)