Major Grounds of Inadmissibility
| Classes of Inadmissibility | Waivers Available? |
| People with communicable diseases like tuberculosis | Yes |
| People with physical or mental disorders that may cause harm to themselves or others | Yes |
| Drug abusers or addicts | No |
| Drug traffickers | No |
| People without proper vaccinations | Yes |
| People with convictions for crimes involving moral turpitude | Yes |
| People who have violated immigration laws | Yes |
| Prostitutes | Yes |
| People with multiple criminal convictions | Yes |
| Spies | No |
| Terrorists | No |
| Nazis | No |
| People likely to become dependent on need-based government assistance | Yes |
Everyone who applies to enter the U.S., no matter how long the person plans to be here or whether the person already has a green card, is checked to see whether he or she is inadmissible. But even though the word “admissibility” sounds like it applies only to someone who is outside the U.S. applying to get in, for immigration purposes, it also applies to people who are already in the U.S. applying for a different status, like permanent residency. They too must be “admissible.” The law treats them like they’re outside the U.S. asking to be let in, even though they’re already inside the United States.
(Source: nolo.com legal encyclopedia)
