Summary: Past studies of illegal aliens revealed that these aliens did not pay all Federal taxes owed, were sometimes on welfare, and held jobs that could be filled by citizens or lawful aliens. There is disagreement about the extent to which illegal aliens are benefiting from federally funded programs, paying taxes, and affecting the labor market. Legal immigration has had a significant impact of Federal assistance programs. About 37,500 newly arrived aliens in five States received about $72 million annually in Supplemental Security Income benefits. Reassessment of immigration policy is needed because of the large number of illegal aliens who are not apprehended, violations of entry conditions by other foreigners, unfair and ineffective immigration laws, and activities of professional smugglers. Problems exist because of poor conditions in some countries, inadequate resources for enforcement, the need for new legislation, and inadequate information. Legislative proposals contain provisions for sanctions against employers who hire undocumented aliens, changing the status of many illegal aliens, increasing enforcement resources, and cooperating with foreign governments to improve their economies.