This study sought to determine the cognitive levels of questioning of end-of-chapter test items accompanying selected fifth-grade science textbooks. The extent to which test items emphasized high level questioning and significant differences among texts in the distribution of knowledge and above-knowledge-level test items were also investigated. Data were derived from 500 test items randomly selected from five most widely used fifth-grade science textbooks in Alabama, California, Tennessee, and Texas. Three raters classified the items according to Bloom's six major taxonomic categories. Collectively, 304 items were judged as assessing knowledge, 169 as assessing comprehension, 26 as application items, and one as an evaluation item. Implications derived from the findings of this research are based on two assumptions that: (1) the use of higher order questions stimulates critical thinking; and (2) tests that accompany textbooks are important guides to instruction and evaluation. In general, it appears that high-order thinking skills are not elicited by end-of-chapter tests in science textbooks and that ready-made tests, which accompany science textbooks, tend to become guides for instruction as well as evaluation. An 87-item reference list concludes the document. (TJH)