Introduction In England, there is no reliable indicator for measuring the occurrence of non-fatal injury. As a consequence, we do not know whether the rates of non-fatal injury are increasing or decreasing. Purpose This paper addresses two questions: what criteria should an indicator of non-fatal injury satisfy, and can we identify an indicator that satisfies these criteria? Method Criteria for a good indicator of non-fatal injury are postulated, and an indicator based on serious long-bone fractures is proposed. Inferences from the literature and the various non-fatal injury data to which we have access are used to justify the criteria, and to test the proposed indicator of serious injury against the criteria. Findings There is significant evidence to justify the use of the following criteria to assess indicators of non-fatal injury: the indicator should reflect the occurrence of injury satisfying some case definition of anatomical damage; the injury cases ascertained should be important in terms of incapacity, impairment, disability, quality of life, cost, and/or threat-to-life; cases should be completely ascertained from routinely or easily collected data; and the probability of a case being ascertained should be independent of social, health services supply and access factors. Our analysis indicates that an indicator based on serious long-bone fracture admitted to hospital is likely to satisfy each of these criteria for a good indicator. Conclusion An indicator of non-fatal injury occurrence based on serious long-bone fractures exhibits favourable characteristics when judged against our criteria for a good indicator.