Alternatives to the standard statewide assessment often are necessary for valid measurement of students with significant disabilities. These alternate assessments must be carefully developed and evaluated with respect to generally accepted psychometric standards. Ideally, these measures should be sensitive to growth and scaled to state tests that are aligned with grade level content standards. In this study, we investigated the technical adequacy of early reading performance tasks for a Grade 3 statewide alternate reading test. Our research hypotheses pertain to (a) equitable measurement function across populations of students, (b) measurement dimensionality, and (c) item difficulty. Using test results obtained from annual testing in one state, our findings suggest that performance tasks are adequate for use in the alternate assessment, and they can be scaled in terms of the statewide testing metric. (Contains 6 tables and 1 figure.)