The cervical curvature of 488 patients with acute whiplash injury was prospectively studied by comparison with 495 asymptomatic healthy volunteers. Plain radiography of the cervical spine in the neutral position was evaluated qualitatively. No significant difference was noted in frequencies of non-lordotic cervical curvature and local angular kyphosis between acute whiplash injury patients and asymptomatic subjects. No significant association was apparent between clinical symptoms and cervical curvature. These results suggest that non-lordotic cervical curvature and angular kyphosis in acute whiplash injury patients constitute normal variants rather than pathological findings.