If the late Stephen Hawking had wanted to settle in Canada, he would likely have been denied. This is because he was disabled. Federal immigration law is designed to exclude people with chronic illness and developmental or genetic difference from permanently settling on health grounds, referred to as medical inadmissibility, with some exceptions. I explore and critique the immigration system based on an ethnography of the medical, legal, and administrative practices governing this bureaucracy published as Screening Out: HIV Testing and the Canadian Immigration Experience. Using findings from people toward whom exclusionary health policy is directed, I argue that immigration medical practices trigger ethical, practical, and professional problems for migrant persons and for the doctors, lawyers, and other practitioners inside and outside Canada whose livelihoods tether them to the immigration program. I provide a series of do-able strategies for legal reform.