Form 601 is a waiver for grounds that would otherwise make an alien not admissible into the United States. In other words, if an alien would be disqualified from obtaining a green card because he/she was charged with a crime or he/she is unlawfully present in the country, Form 601 may allow him/her to still obtain their green card. So, even if you don’t think you would qualify for a green card, you may still be eligible for one by properly filing Form 601 along with your application.