  We propose to create and stabilize long-lived macroscopic quantum
superposition states in atomic ensembles. We show that using a fully quantum
parametric amplifier can cause the simultaneous decay of two atoms, and in turn
create stabilized atomic Schr\"{o}dinger cat states. Remarkably, even with
modest parameters these atomic cat states can have an extremely long lifetime,
up to \emph{four orders of magnitude} longer than that of intracavity photonic
cat states under the same parameter conditions, reaching \emph{tens of
milliseconds}. This lifetime of atomic cat states is ultimately limited to
\emph{several seconds} by extremely weak spin relaxation and thermal noise. Our
work opens up a new way towards the long-standing goal of engineering
large-size and long-lived cat states, with immediate interests both in
fundamental studies and noise-immune quantum information processing.
