  We consider the decay of an intermediate mass Higgs boson into hadrons up to
order O(\alpha_s^3). The results from the diagrams containing only light
degrees of freedom were recently computed in a previous work by K.G. Ch. (Phys.
Lett. B 390 (1997) 309). In this letter the remaining contributions involving
the top quark are evaluated analytically using an effective field theory
approach. Coupled with the previous result the present calculation determines
the complete next-next-to-leading order correction to the hadronic decay rate
of an intermediate mass Higgs boson.
