This article presents the findings of the first linguistic analysis of sign language interpreting carried out in Australia. A study was conducted on 10 Australian Sign Language/English interpreters to determine the rate and occurrence of interpreting omissions and the interpreters' level of metalinguistic awareness in relation to their production of interpreting omissions. After videotaping interpretations, analyzing the interpreters' output, and conducting post-interpreting task reviews and retrospective interviews, the authors report that all the interpreters appeared to have high levels of metalinguistic awareness with regard to their production of interpreting omissions. This finding led to the definition of five categories of interpreting omissions: (1) conscious strategic; (2) conscious intentional; (3) conscious unintentional; (4) conscious receptive; and (5) unconscious omissions. The findings of this study can be applied in the education of signed and spoken interpreters not only in Australia but also worldwide. (Contains 6 tables, 5 figures, and 5 notes.)