This paper describes an investigation into the type of listening test that might serve as an assessment instrument of English language teachers as part of a teacher certification test — the Hong Kong English Language Benchmark Test. The paper first describes the benchmarking initiative in Hong Kong to orient the reader to the nature and purpose of the Listening Test. The paper then describes a case study where groups of pre-service and in-service English language teachers were administered audio and video versions of the same test, after which a survey was conducted of their opinion of the audio/video mode of assessing listening. Scores on the two test modes (as well as on an anchor test) indicated no significant differences between the two scores of the two groups. Further, although some of the test takers from the audio test-taking group said they would have preferred to have taken the test via video, the video test-taking group felt that not only had they gained no advantage from the video mode, they felt they might have done better had they not been distracted by the visual images, and by having to look up and down from question paper to screen. As a high-stakes certification test for English language teachers, the conclusion that is drawn is that the listening comprehension test should be implemented via an audio, and not video, mode.