The Armed Services Vocational Aptitude Battery (ASVAB) is used to select and classify enlisted personnel. Although the factor structure of the ASVAB has been assessed and compared to similar aptitude tests, no thorough factor reference study has been done with the current ASVAB configuration. To examine the factor structure of the ASVAB, 46 tests from the Kit of Factor Referenced Cognitive Tests (the Kit) and the 10 ASVAB subtests were administered to a sample of airmen. Because 56 tests were investigated, it was impossible to have every examinee receive every test. Matrix sampling was used to pair each test with each of the other tests. After consideration of descriptive statistics and after editing, the data were assembled into a correlation matrix for exploratory and confirmatory factor analysis. Matrix sampling requires special factor analytic methods. The factor analyses indicated that the correlation structure among the ASVAP scores required three factors to explain, whereas that in the Kit scores required six. The factors used to explain the ASVAB can largely be placed within the factor space of the Kit factors, indicating that the abilities measured by the ASVAB are a subset of the abilities measured by the Kit. Future research to enhance selection and classification should focus on abilities not currently measured by the ASVAB.