This report presents results for the first trial school-district-level science assessment in NAEP at grades 4 and 8. Ten urban public-school districts voluntarily participated: Atlanta City, Austin Independent School District, Boston School District, Charlotte-Mecklenburg Schools, City of Chicago School District 299, Cleveland City School District, Houston Independent School District, Los Angeles Unified, New York City Public Schools, and San Diego Unified. Student performance is reported in terms of average scale scores on the NAEP science scale and the percentages of students who attained the achievement levels set by the National Assessment Governing Board. Comparisons are made to public school results in large central cities and the nation. Student performance is reported by race/ethnicity, eligibility for free/reduced-price school lunch, and gender. At grade 4, in 7 of the 10 districts, students performed as well as or better than students in large central cities. Two districts had higher average science scores than the average in large central cities. At grade 8, in 6 of the 10 districts, students performed as well as or better than students in large central cities. Students in three districts had higher average scores and higher percentages performing at or above Basic compared to large central cities.