Forty-one 10th grade biology tests prepared by commercial publishers, test bureaus, and the Biological Sciences Curriculum Study were analyzed using the six major categories of Bloom's Taxonomy of Educational Objectives Handbook I: Cognitive Domain. Of the 2,689 test items classified, 71.88% were Knowledge, 15.17% Comprehension, 11.49% Application, 1.37% Analysis, 0.04% Synthesis, and 0.04% Evaluation. Tables showing the percentage of items at each level for each test are given. Only BSCS tests reflected levels above Application, and of these, only the Process of Science Test used all six levels of the Taxonomy. A check on the classification of the items by a panel of twelve judges produced an overall agreement of 83.9%. (AL)