Over the past decade, bioethicists have increasingly debated the moral status of research participation, or more specifically, whether there is a moral obligation to participate in biomedical research. This paper critically examines some of the key reasons for, motivations behind and consequences of conceiving research participation as a moral obligation. I argue that some important underlying philosophical issues have been neglected in the current debate, as well as some of the motives driving the arguments, and that reflecting on the increasingly global nature of biomedical research practices can help draw out what is ethically at stake in conceiving research participation as obligatory. I conclude that research participation in general should not be regarded as a moral obligation. These leaves open other theoretical possibilities: (1) that in some special cases, on some conditions, with some populations, a specific research study may be morally obligatory and (2) that research participation in general could be regarded as an ‘imperfect duty’, i.e. not an action that individuals must do, but a possible action that individuals may have a duty to take into reasonable consideration in the process of weighing their various options.