Federal law requires that all students, including students with disabilities, participate in state assessments used for accountability purposes. It also requires states to assess students in several content areas, including science. Most students with disabilities take the general science assessment with or without accommodations, but a few students with the most significant cognitive disabilities participate in alternate assessments based on alternate achievement standards (AA-AAS). The purpose of this analysis was to learn more about the characteristics of states' science AA-AAS in 2014-2015. Data for this report were gathered by examining information that was publicly available on state websites. Key findings include: (1) Most states' science AA-AAS covered the life science/biology, earth science/earth and space science, and physical sciences/physics content domains at all grade levels; (2) In many states some content domains assessed differed between the general assessment and the AA-AAS; (3) In some states more content domains were covered on the AA-AAS than on the general assessment and in others fewer content domains were covered; and (4) More than half of the states had item-based AA-AAS, while about a third of the states used portfolios; fewer than 10 used rating scales, either alone or in combination with another approach. Although federal regulations do allow states to define the complexity, depth, and breadth of the AAAAS, the apparent lack of consistency in the domains assessed suggests that some students with significant cognitive disabilities may not be getting access to the same rigorous grade-appropriate content. States' evolving assessment systems provide an excellent opportunity for states and consortia to consider the content assessed by the science AA-AAS. The following are appended: (1) AA-AAS Science Content Domains by State; (2) General Assessment and AA-AAS Science Comparisons; and (3) Assessment Approach Types and Response Formats.