This article seeks to examine the relationship between scientific output and knowledge economy index in 10 South East Asian countries (ASEAN). Using bibliometric data of the Institute of Scientific Information, we analyzed the number of scientific articles published in international peer-reviewed journals between 1991 and 2010 for Vietnam, Cambodia, Laos, Thailand, Myanmar, Malaysia, Indonesia, Brunei, the Philippines, and Singapore. During the 20-year period, scientists from the ASEAN countries have published 165,020 original articles in ISI indexed journals, which represents ~0.5% of the world scientific output. Singapore led the region with the highest number of publications (accounting for 45% of the countries’ total publications), followed by Thailand (21%), Malaysia (16%), Vietnam (6%), Indonesia and the Philippines (5% each). The number of scientific articles from those countries has increased by 13% per year, with the rate of increase being highest in Thailand and Malaysia, and lowest in Indonesia and the Philippines. At the country level, the correlation between knowledge economy index and scientific output was 0.94. Based on the relationship between scientific output and knowledge economy, we identified 4 clusters of countries: Singapore as the first group; Thailand and Malaysia in the second group; Vietnam, Indonesia and the Philippines in the third group; and Cambodia, Laos, Myanmar and Brunei in the fourth group. These data suggested that there was a strong relationship between scientific research and the degree of “knowledgization” of economy.