The purpose of this study was to determine the extent that diagrammatic literacy is necessary for success on standardized science tests at the late-elementary and middle grade levels. Towards this goal, we quantified the frequency, form and function of graphical representations on select state science tests. 985 tests items from 14 states were analyzed with 52.7% of the test items including graphical representations. The majority of these graphics, 79.5%, contained information that was essential for correctly answering the questions. The paper also discussed the trends of graphical representations in grade levels and alignment to national standards, following with teacher-implications. (Contains 5 tables and 8 figures.)