  KamLAND has been used to measure the flux of $\bar{\nu}_e$'s from distant
nuclear reactors. In an exposure of 162 ton$\cdot$yr (145.1 days) the ratio of
the number of observed inverse $\beta$-decay events to the expected number of
events without disappearance is $0.611\pm 0.085 {\rm (stat)} \pm 0.041 {\rm
(syst)} $ for $\bar{\nu}_e$ energies $>$ 3.4 MeV. The deficit of events is
inconsistent with the expected rate for standard $\bar{\nu}_e$ propagation at
the 99.95% confidence level. In the context of two-flavor neutrino oscillations
with CPT invariance, these results exclude all oscillation solutions but the
`Large Mixing Angle' solution to the solar neutrino problem using reactor
$\bar{\nu}_e$ sources.
