This study examined composing processes of six graduate ESL writers in timed essay situations. The participants’ composing behaviors were videotaped and they were asked to retrospect their composing processes after they completed their timed essays while watching the video of themselves composing. The stimulus recall data were transcribed and analyzed using coding schemes. The analyses of the participants’ composing processes show that they were not able to go through composing steps they normally do in drafted writing situations. Instead they were forced to go through a linear composing process and were not able to enjoy heuristic discovery. The findings of this study support the claim that timed essay is a special form of writing and that essay exams do not necessarily produce a representative sample of test takers' writing ability in target language use domains.