The prospect that the maritime transportation of irradiated nuclear fuel (INF), plutonium and radioactive wastes can be expected to continue for the foreseeable future, together with widely expressed concern that an accident may occur to a ship carrying such cargo, has meant that regulatory safeguards have come under intense scrutiny in recent years. The paper describes the actions taken by the International Maritime Organisation (IMO) aimed at ensuring the safety of ships engaged in such activity, culminating in the decision of its Maritime Safety Committee (MSC) in May 1999 to make compliance with the INF Code mandatory. In relating the above progress, the paper draws attention to a number of issues raised by Governments in the IMO which have so far gone unaddressed, these issues having also been highlighted in responses to a questionnaire circulated to coastal states. The paper reviews the legal issues associated with the right of emergency access to a foreign port by a ship transporting nuclear materials, the availability of a safe haven being crucial in the event that critical repairs or salvage operations are necessary. Finally, the paper considers whether seabed characteristics should be assessed in determining the routeing of such ships, bearing in mind that ocean floor topography and water depth will be crucial in determining whether recovery of nuclear materials would be practicable in the event of sinking of a ship.