The study explored the awareness of morphemic knowledge among young adult learners in the ESL context. Morphological Relatedness Test and Morphological Structure Test (adapted from Curinga, 2014) were two important tools used to assess the students' morphemic knowledge in this study. The tests measured the students' ability to reflect and manipulate morphologically complex derived words in English. Paired sample t-test was utilized to report the results of this quantitative study. The results demonstrated that young adult learners have modest ability in both tasks i.e. to reflect and manipulate morphologically complex derived words. In fact, students' performance was poorer in manipulation task compared to the reflective task. The study suggests that explicit instruction on morphology units can be introduced as a strategy to develop morphemic knowledge among Malaysian young adult learners. The study further proposes that young adult learners can expand their vocabulary by analyzing the meaningful parts within words through morphological knowledge.