U.S. Customs and Border Protection (CBP) has expanded on its explanations of the grounds of inadmissibility for which one might require a Form I-192 waiver. Form I-192, Application for Advance Permission to Enter as a Non-Immigrant and Inadmissible Canadian Information In general, you might be denied entry: If you have a communicable disease, If you have a criminal record for crimes of moral turpitude, For possession of or trafficking in a controlled substance, If you have any involvement with terrorism or terrorist organizations (no waivers can be approved for this category) , If you have trafficked in persons, If you have been involved in money laundering, If you might become a public charge because of limited financial resources, If you have been previously removed (deported) or have overstayed a previous period of admission to the United States A comprehensive list of the legal descriptions can be found here: Legal Descriptions (opens a PDF document)