Addition of 2.0wt% or 0.3wt%Sn proved to be very effective in improving the permanent magnetic properties of NdFeNbB magnets. additions result in the increase in the Hci and temperature dependence due to formation of (NdDy)-rich phase and grain refinement of phase. This improvement of the coercivity stability of the magnets from the addition of Sn is attributed to the smoothing effect of the Sn addition at the grain boundaries. The magnetic properties, the temperature dependence and Curie temperature of NdFeNbB with and Sn combined addition were found to be considerably improved