The conceptualization of the term "psycholinguistic ability" led to the definition of an area of language behavior that is not well represented in achievement tests in English nor in existing tests of verbal intelligence. Thus, the Linguistic Ability Test (LAT) was designed, pilot-tested, revised, and field-tested in an attempt to measure the skills implied by psycholinguistic ability. The field testing involved 106 fourth- and 105 sixth-grade students whose mean IQ score was 104.6 points. The LAT showed very high reliability (Hoyt internal consistency) at both grade levels. The item analysis data are presented for the entire test (148 items) as well as for the 15 subsections of the test. Mean scores at each grade level and for male and female subjects are given as well as the intercorrelations of the 15 subsections, the total test, and Otis IQ score. The future importance of the LAT is projected. The test, along with its planned revisions, is included in the report. (Author/JD)