Unintentional islanding is a critical issue in the integration of distributed generation to the power distribution network. Islanding detection or anti islanding protection for a distribution generation is important in this regard. The paper proposes a new islanding detection scheme in time domain based on Mathematical morphology. The detection technique uses the Morphological gradient wavelet(MGW) to operate on voltage and current in any phase. The Norm of the voltage and current after passing through the MGW is calculated. This ratio is used as a criteria for detecting an island. Simulations are carried out for different islanding and non islanding events to study the effectiveness of the algorithm. © 2017 IEEE.