The study investigated how second language (L2) learners self-assessed word knowledge on a page of text taken from a graded reader. The case study subjects were five Thai high school learners of English. They were asked to assess their word knowledge using a page of continuous text. Data gained through observation, interviews, self-assessment and a translation test showed that such self-assessment of word knowledge resulted in learners using various reading techniques from simple translation to more complicated guessing from context. The results provide some insight into how self-assessment of word knowledge with graded readers is carried out and provides evidence to support the value of self-assessment as an easy procedure to direct learners to an appropriate reading level as suggested by the scholars in the field (Bamford & Day, 2004; Day & Bamford, 1998; Waring, 1997). Suggestions for pedagogical practice are given. (Contains 2 tables and 2 notes.)