The importance of technology assessment(TA) is increasingly emphasized, however, the question of what is TA is ambiguous yet. This article traces the concept of TA, and tries to identify the its meaning and current issues. It argues that the ambiguity of TA concept is not tragedy, but blessing in its growth. We came to know that one should consider for a successful TA some issues : institutional conditions, methodology, functions and timeliness. And they should also be considered in the TA-building process of Korea which is now on.