The Boltzmann equation for inelastic Maxwell models is considered to
determine the rheological properties in a granular binary mixture in the simple
shear flow state. The transport coefficients (shear viscosity and viscometric
functions) are {\em exactly} evaluated in terms of the coefficients of
restitution, the (reduced) shear rate and the parameters of the mixture
(particle masses, diameters and concentration). The results show that in
general, for a given value of the coefficients of restitution, the above
transport properties decrease with increasing shear rate