Based on a review of some of the most promising approaches to aptitude testing in the literature this paper proposes a novel task piloted at the Center for Translation Studies of the University of Vienna. The SynCloze test combines an auditory cloze exercise with a task requiring high expressional fluency, that is, rapidly finding contextually appropriate synonymic sentence completions. The rationale and design of the SynCloze test as well as the scoring method, which takes into account both the degree of accuracy and the speed of response, are described. The results of four rounds of testing involving some 120 students in the final stage of their undergraduate studies show that the test effectively discriminates between undergraduate novices and a control group of interpreting students, and students for whom the test language (German) is the A vs. the B language. Most significantly, the test scores correlate, albeit moderately, with students’ performance on an intralingual consecutive interpreting exam at the end of the course.