This paper focuses on two mega natural disasters that occurred in Asia: the Great East Japan Earthquake (GEJE) in March of 2011 and the Chao Phraya Floods from August to December of 2011. In each hazard, we investigated and analyzed actual situations through field survey and interviews to victims. We identified the problems of existing systems in the GEJE case, especially problems in urban planning for high-risk areas. We also found problems in relation to inviting foreign companies by special deregulation policy to areas that were revealed as having high flood-risk at the wake of the Thai flood, as well as serious damage induced by worldwide concatenation in the supply chains of various industries. Through these reviews, we points out lessons to be learned from two unprecedented disaster occurred in 2011. We also described lessons learned and recommend countermeasures for mega disasters, discussing what measures are required to build a disaster-resilient society in thefuture.