  We report the discovery of time lags in the cross-spectra of the X-ray light
curves of the Seyfert galaxy NGC 7469. This behavior is common in Galactic
black hole and neutron star binaries, and is in the sense that harder X-rays
are delayed with respect to the soft with a time lag approximately proportional
to the Fourier period. At the longest period probed by our observation we find
a time lag of approximately 3.5 hours between the 2-4 and 4-10 keV X-rays. A
similar lag and period dependence is found comparing the 2-4 and 10-15 keV
light curves, albeit with less significance. We find the coherence function of
the light curves to be close to 1. The implications of these results for the
X-ray production mechanism in active galactic nuclei (AGN) is discussed.
