Giving amnesty to illegal immigrants will greatly increase long-term costs to the taxpayer. Granting amnesty to illegal immigrants would, over time, increase their use of means-tested welfare, Social Security, and Medicare. Fiscal costs would rise in the intermediate term and increase dramatically when amnesty recipients reach retirement. Although it is difficult to provide a precise estimate, it seems likely that if 10 million adult illegal immigrants currently in the U.S. were granted amnesty, the net retirement cost to government (benefits minus taxes) could be over $2.6 trillion.