This study examines the differences of approaches to second language testing in West Germany in regard to linguistic bases, pedagogical aims, and the desired degree of standardization and empirical quality control. One approach demands a curriculum-integrated diagnosis of language development aiming at a highly differentiated description of the individual second language proficiency level to determine appropriate therapeutic procedures. A second approach demands the development of standardized language tests that are objective, reliable, and valid. Investigation of the C-Test suggests that it fills all of the requirements of the second approach, and is useful in classroom testing, selection, classification, and placement. The lack of suitable standardized tests for second language learners in Germany has stimulated development of informal testing procedures, but most have not been properly researched and are cumbersome to administer. Standardized tests such as the C-Test have the advantage of economy of administration and interpretation, and could play an important role in improving the educational opportunities of immigrant children in Germany. (MSE)