The 2000s have witnessed the arrival and growing popularity of randomized controlled experiments (RCTs) in Development Economics. Whilst this new way of conducting research on development has unfolded important insights, the ethical challenge it provokes has not yet been systematically examined. The present article aims at filling this gap by providing the first ad hoc discussion of the moral issues that accompany the use of RCTs in Development Economics. Claiming that this new research agenda needs its own, specific set of ethical guidelines, we expose the six ethical problems that these experiments potentially provoke and that should therefore be carefully assessed by ethics committees before an RCT is launched and by scholarly journals before its results are published.