A new empirical model is presented for the current-voltage (I-V) characteristics of AlGaN/GaN high electron-mobility transistors (HEMTs). This model is capable of describing the current collapse effect of HEMT Devices, and solves the discontinuous problem of the second derivative of drain current (Ids) in Agilent EEHEMT1 model. Excellent modeling of the measured drain current, its first (trans-conductance), second and third derivatives with respect to gate voltage (Vgs) for multiple drain biases is demonstrated.