We describe the construction and assessment of a new matched employer-employee data set, the 1990 Decennial Employer-Employee Dataset (1990 DEED). By using place of work name and address, we link workers from the 1990 Long Form Sample to their place of work in the 1990 Standard Statistical Establishment List. The resulting data set is much larger and more representative across regional and industry dimensions than previous matched data sets for the United States. The known strengths and limitations of the data set are discussed in detail.