The ten members states have agreed that political stability and long term economic growth could only be attain if they all cooperate (ASEAN Charter). However, with the expansion of Cambodia,Laos, Myanmar, and Vietnam (CLMV), political and economical disparities have ensued between the oldand the new member states. Moreover, the development gap among the member states in the region has also persisted. The challenges of the CLMV countries and the role of development partner will be discussed and examined.