A trainability test is a means of estimating the suitability of a candidate for a course of training. Grounds for assessment are provided by the construction of a learning task which replicates some key aspects of the skill to be learned and the procedure by which they must be aquired. Such a test, based on the learning of medical terms, was given to 129 student nurses at five London general hospitals. Lower test scores were found to be associated with high drop-out for UK nurses and it is assumed that for them the test was measuring a capacity relevant to performing satisfactorily on the course. Low-scoring overseas nurses, however, were less likely to leave than their UK counterparts. Discussion of the reasons for this includes reference to the general phenomenon of lower wastage rates among overseas nurses, evidence about overseas nurses' attitudes towards completing the course and the possibility that this test, like others, somewhat underestimated the potential of overseas candidates. Methods are considered for making the test as valid for overseas as for UK candidates.