Displacement-damage induced degradation in InAlN/GaN structures is studied for different proton fluences, from 110 14 p/cm 2 to 410 14 p/cm 2 , at 3MeV. DC analysis reveals that devices experience a V TH positive shift and an increase of the R ON , following a linear trend with the proton radiation fluence, as a consequence of the creation of acceptor-like traps. Furthermore an increase of the diode gate current is noticed. Pulsed measurements indicate an increase of the so called “current collapse”, especially when a high gate drain voltage difference is applied, as a consequence of the performances variation in the dynamic max g m , V TH shift and R ON .