Prevention of head and spinal cord injuries is defined as a reduction in the incidence of these disabilities. Accurate incidence data are fundamental to any prevention program. The current approaches toward determining incidence rates for head and spinal cord injuries are summarized. Previous research has focused on passive surveillance systems and population-based registries. An alternative system for monitoring the incidence of head injuries is discussed that uses a surveillance methodology called capture-recapture. This method employs multiple population-based sources to identify cases and uses the cases that overlap between the sources to estimate the degree of undercount in the population. This estimate in turn is used to produce an ascertainment-corrected incidence estimate. Through the use of methods such as capture-recapture, accurate monitoring of the incidence of head and spinal injuries across developing and developed countries is indeed feasible.