Summary: GAO discussed: (1) federal agencies' implementation of the Immigration Reform and Control Act (IRCA); and (2) employment discrimination complaints and other problems resulting from IRCA implementation. GAO noted that: (1) data suggested that IRCA implementation reduced illegal immigration and made it more difficult for unauthorized aliens to find work in the United States; (2) both the Immigration and Naturalization Service and the Department of Labor generally carried out their responsibilities to educate employers about IRCA requirements and identify and fine violators; (3) there was no evidence of plaintiffs making frivolous IRCA discrimination complaints to harass employers; (4) a survey of 4.6 million employers indicated a serious pattern of illegal national origin discrimination attributable to IRCA, with about 19 percent of employers not hiring any persons with foreign appearances or accents, applying work eligibility verification procedures only to those persons with foreign appearances or accents, employing only persons born in the United States, and not hiring persons with temporary work eligibility documents; (5) about 78 percent of employers preferred a simpler or better verification system; and (6) illegal employment discrimination appeared to be primarily caused by employers' lack of understanding of requirements, employers' confusion about eligibility determinations, and the prevalence of fraudulent documents.