This study examines the problems of constructing and administering a test of spoken English for Vietnamese EFL teacher-trainees. In an attempt to standardize the assessment, a planned oral interview was pilottested with a group of ten Vietnamese EFL teachers currently enrolled in a Graduate Diploma Course in TESOL at the Canberra College of Advanced Education, Australia. Results of the study indicate that the validity and reliability of such measurement can be achieved if certain carefully outlined procedures in planning the test and training the testers are carefully followed. Given the close relationship between testing and teaching, it is suggested in this study that there could be an improvement in the teaching of spoken English to Vietnamese EFL teacher-trainees if (i) the amount of time allocated to testing oral proficiency in the curriculum was increased, (ii) Vietnamese EFL teachers were provided with formal training in language test construction, and (iii) research on EFL oral testing was encouraged. Further, this study recommends co-operation between TEFL institutions in Vietnam to develop standard instruments for the assessment of spoken English of EFL teacher-trainees on a national level.