We have been conducting upper air ozone and water vapor soundings in Ho Chi Minh and Hanoi, Vietnam in collaboration with Vietnam Meteorological and Hydrological Administration. The purpose of this observation is to clarify the ozone and water vapor exchanges between the mid-latitude stratosphere and the tropical troposphere associated with the Asian summer monsoon circulation. We started the observation on June 29 at the Ho Chi Minh observatory and on July 2 in the Hanoi observatory, and have been launching the balloons once in two days at the both observatories. (SYO)