Standardized achievement and aptitude tests may be of very limited value in making placement or instructional decisions about bilingual students. The practice of categorizing standardized test scores by ethnic groups obscures the difficulties of administering and interpreting tests taken by bilinguals. Individuals who are bilingual have two language systems that overlap and are distinct; both are relied upon in a variety of ways, depending on the linguistic and communicative demands of everyday settings. It is not yet known how to measure the extent to which one of the languages of a bilingual student influences the other, or even how to describe bilingual competence. In test-taking situations, the switching and other linguistic adaptations of bilinguals create notable differences from the way that monolingual students perform. Because standardized tests in any language are biased in favor of native speakers, low test scores received by bilinguals are often interpreted as evidence of deficits or even disorders. The following commonly used options for administering standardized tests to limited English speakers are reviewed: (1) nonverbal tests; (2) translated tests; (3) use of interpreters; (4) tests that are norm-referenced in the primary language; and (5) true bilingual assessment. The educational opportunities of bilingual students would be improved by expanding diagnostic protocols to include information beyond standardized test scores and by creating assessment that is more directly based on curriculum. A list of nine references is appended. (FMW)