KamLAND-Zen searches for neutrinoless double beta (0nbb) decay with Xe-136 loaded liquid scintillator. Results from "KamLAND-Zen 400" are based upon data collected from 2011 to 2015 and we obtained the most stringent lower limit for 0nbb decay half-life of 136Xe, 1.07*10^26 yrs at 90% C.L. Next phase, "KamLAND-Zen800" is in preparation and will start data taking in this year. We will report the current status. Future prospects of the experiment, "KamLAND2-Zen" is also presented