Many countries encourage immigration, yet almost without exception they impose medical conditions on the admissibility of prospective immigrants. This paper examines the ethical defensibility of this practice. It argues that the neighbourhood principle, which states that we owe a greater duty to neighbours than to strangers, when properly understood, extends to all human beings, that economic and safety considerations play only a limited role in ethically underwriting an exclusionary policy, and that medical immigration criteria should be harmonized with treatment eligibility (...) criteria for citizens of the relevant countries themselves. (shrink)