'Whiplash' injuries are a common cause of road traffic accident (RTA) related morbidity. However, few epidemiological studies have investigated risk factors associated with the occurrence of such injuries. The purpose of this study was to examine relationships between vehicle and occupant factors and the incidence of 'whiplash' in drivers with recent experience of a rear-end impact in an RTA. A cohort of 246 car drivers with recent experience of a rear-end impact in the Adelaide metropolitan area was recruited. Structured telephone interviews were used to obtain information about driver demographics, the circumstances of the crash, and injuries resulting from the crash. Two factors were identified as independent risk factors for 'whiplash' injury: a history of neck injury (adjusted odds ratio = 4.50, 95 per cent confidence interval 1.97-10.28) and female sex (adjusted odds ratio = 2.08, 95 per cent confidence interval 1.13-3.82). The relative weight of the striking vehicle to the driver's vehicle was also positively associated with risk of 'whiplash' injury. There was no evidence that the driver's occupation or level of education are predictors of occurrence. Methodological aspects of the study which might have resulted in bias are discussed and suggestions are given for overcoming these in future work.