  In this paper, we study the persistence of spatial analyticity for the
solutions to the Klein-Gordon-Schr\"{o}dinger system, which describes a
physical system of a nucleon field interacting with a neutral meson field, with
analytic initial data. Unlike the case of a single nonlinear dispersive
equation, not much is known about nonlinear dispersive systems as it is harder
to show the spatial analyticity of coupled equations simultaneously. The only
results known so far are rather recent ones for the Dirac-Klein-Gordon system
which governs the physical system when the nucleon is described by Dirac spinor
fields in the case of relativistic fields. In contrast, we aim here to study
the Klein-Gordon-Schr\"{o}dinger system that works in the non-relativistic
regime. It is shown that the radius of spatial analyticity of the solutions at
later times obeys an algebraic lower bound as time goes to infinity.
