The study was aimed at examining the usefulness of the English Placement Listening test (EPT) in Fall 2010 at Iowa State University (ISU) by using the current argument-based validation approach with a focus on four main inferences constructing the validity argument. Both qualitative and quantitative methods were employed. The results contributed both positive and negative attributes to the validity argument for the EPT Listening Fall 2010 test. The qualitative examination on the test specification and the test booklet showed that the test was authentic with a good distribution of question types and test item indices. In specific, the 30 test items were equally divided into comprehension and inference questions with 90% and 70% of them falling within an acceptable difficulty range, and an acceptable discrimination range respectively. General statistical analyses of the EPT Listening Fall 2010 test score set of 556 test takers produced a normal distribution with a reliability of nearly 0.70. Moreover, the correlation analyses among different set scores of the EPT Fall 2010 test takers supported the usefulness of the EPT test in discriminating proficiencies of the test takers besides their TOEFL scores. However, numerous weaknesses were detected such as an incomplete test specification, weak strengths of the correlational relationships between the EPT test and the TOEFL tests (r<0.6). The study provided an evidence on the importance of the operation of the EPT test at ISU and lead to some recommendations on supporting the validity argument for the test.