ABSTRACT  This study compared low and high risk first-year high school foreign language learners on measures of cognitive, foreign language, and native language performance. Low risk learners were those who had made an A or B in the first-quarter foreign language course, were identified by their foreign language teacher as good language learners, and scored low risk on an author-designed foreign language screening instrument (Ganschow and Sparks, 21); high risk learners made a D or F in the first quarter, were identified by their foreign language teachers as poor language learners, and scored high risk on the screening instrument. Significant differences between the groups were found on most assessed measures of native language phonology and syntax and on the Short and Long Forms and all subtests of the Modern Language Aptitude Test. No differences were found on semantic measures. Based on results of native and foreign language assessments, the authors infer that students with foreign language learning difficulties have subtle but underlying native language learning difficulties, especially in the phonological and syntactic codes of language. Implications for the diagnosis and teaching of students with foreign language learning problems are discussed.