We calculate the relic density of the lightest neutralino in a supersymmetric seesaw type-II (``triplet seesaw) model with minimal supergravity boundary conditions at the GUT scale. The presence of a triplet below the GUT scale, required to explain m
easured neutrino data in this setup, leads to a characteristic deformation of the sparticle spectrum with respect to the pure mSugra expectations, affecting the calculated relic dark matter (DM) density. We discuss how the DM allowed regions in the (m_0,M_{1/2}) plane change as a function of the (type-II) seesaw scale. We also compare the constraints imposed on the models parameter space form upper limits on lepton flavour violating (LFV) decays to those imposed by DM. Finally, we briefly comment on uncertainties in the calculation of the relic neutralino density due to uncertainties in the measured top and bottom masses.
