Let G be a semi-simple
connected noncompact Lie group with finite center and K a fixed maximal compact
subgroup of G. Fix a Haar measure dx on G and let I1(G) denote those functions in
L1(G,dx) which are biinvariant under K. The purpose of this paper is to prove that
if f ∈ I1(G) is such that its spherical Fourier transform (i.e., Gelfand transform) f is
nowhere vanishing on the maximal ideal space of I1(G) and f “does not vanish too
fast at ∞”, then the ideal generated by f is dense in I1(G). This generalizes earlier
results of Ehrenpreis-Mautner for G =SL(2,R) and R. Krier for G of real rank
one.