This report provides information on the characteristics and work patterns of United States agricultural workers performing seasonal agricultural services (SAS) during fiscal year 1990. SAS crops include the majority of nursery products, cash grains, field crops, and all fruits and vegetables. More than 2,000 personal interviews with SAS workers were conducted by the National Agricultural Workers Survey (NASW). Data on personal characteristics of seasonal agricultural workers include: (1) age; (2) gender; (3) marital status; (4) national origin and ethnicity; (5) the effect of the Immigration Reform and Control Act 1986 (IRCA) on legal status; (6) literacy, schooling, and English skills; (7) family residence and work-site household composition; and (8) income, assets, and use of government programs. Information on employment patterns and job characteristics include employment history and labor supply, characteristics and patterns of SAS employment, characteristics and patterns of non-SAS employment, and characteristics and patterns of nonwork periods and periods spent abroad. Regional differences in worker characteristics, job characteristics, and employment patterns are outlined. The appendix describes statistical procedures used. This report contains 41 figures, 3 tables, and 3 maps. (LP)