Whiplash injuries were studied prospectively in 151 patients. Patterns of injury and recovery were found not to depend on the type of accident. Clinical and radiological findings were correlated with the possible pathological bases for the symptoms and signs; some of these were found to be unlikely to be contributors to the clinical picture. The factors which might contribute to a delay in recovery were reviewed, and compensation claims were found not to affect outcome significantly. It is suggested that many patients have sustained an important injury, the exact nature of which remains unclear.