Critical thinking has increasingly been seen as one of the important attributes where human capital is concerned and in line with this recognition, the tertiary educational institutions worldwide are putting more effort into designing courses that produce university leavers who are critical thinkers. This study aims to investigate the critical thinking ability of the postgraduate students in threaded discussion. Participants of the threaded discussion were the postgraduate students of a faculty of a public university located in Klang Valley. Data was collected from the postgraduate courses' threaded discussion assignment mediated via a learning management. Overall, four threaded discussion transcripts were collected and used as the source of data of this study. The researcher assessed the four threaded discussion transcripts based Newman et.al (1995) content analysis framework. Results showed that the participants' postings mainly reflected their critical thinking ability in terms of being able to include relevant (R+ positive critical thinking indicator), clear (AC+ positive critical thinking indicator), novel (N+ positive critical thinking indicator) and justified (JS+ positive critical thinking indicator) input into the threaded discussion. It was found that in the postings, the participants integrated a lot of their personal experience into the discussion (O+ positive critical thinking indicator) and were able to link their ideas coherently (L+ positive critical thinking indicator). However, it was found that the participants generally lacked the ability to critically evaluate their peers' or their own postings. [For the full proceedings see ED557181]