This paper develops methods for constructing asymptotically valid conf
idence intervals for the date of a single break in multivariate time s
eries, including I(0), I(1), and deterministically trending regressors
. Although the width of the asymptotic confidence interval does not de
crease as the sample size increases, it is inversely related to the nu
mber of series which have a common break date, so there are substantia
l gains to multivariate inference about break dates. These methods are
applied to two empirical examples: the mean growth rate of output in
three European countries, and the mean growth rate of U.S. consumption
, investment, and output.