In 1954, the Bureau of Posts overprinted and surcharged definives stamps to mark the Manila Conference.
On September 8. 1959, the fifth anniversary of the signing of the Manila Pact, two commemorative stamps were issued featuring the Philippines Congress Building (now the National Museum), the site of the Manila Conference of 1954.
Congress of the Philippines
First Day of Issue Cancellation
The SEATO emblem was included in the first day of issue cancellation.
First Day Covers
1960 SEATO Conference Washington
The Sixth Annual Conference of SEATO began in Washington on May 31, 1960. The U.S. issued a 4 cent commemorative stamp to mark the occasion.