This study explores how much of omissions and mistranslations in English-Korean consecutive interpreting are related to the problems in note-taking, and investigates ways to reduce omissions and mistranslations in interpreting through improving note-taking. Eleven first semester students in an interpreting and translation graduate program participated in the study. They interpreted a video clip on the US-Korea relationship as part of their mid-term exam. Their interpreting was recorded, transcribed and analyzed in conjunction with their notes and the source text. The omissions and mistranslations in the interpreting were tracked back to their notes to see whether and how they were marked on the notes, and how that in turn affected the interpreting output. Analyses found that around 80% of omissions and 50% of mistranslations were absent from the notes; 50% of mistranslations were marked on the notes but with some issues. Further analysis of the notes revealed three patterns of note-taking that mostly lead to mistranslations: 1) poor structuring, 2) wrong key-words, 3) unrecognizable symbols and abbreviations. Pedagogical implications and limitations of the study are discussed.