Computed tomographic (CT) examinations of the brain were reviewed in 85 patients with a chief complaint of headache and in 22 patients with temporal lobe epilepsy in an attempt to assess the yield and cost-effectiveness in these 2 clinical settings. Lower bounds for the costs of case finding were calculated using probabilistic estimates. In patients with headache and no objective neurologic findings, no abnormal CT examinations were found. On the other hand, 34% of patients with headache and associated objective neurologic findings had abnormal CT studies. No abnormal CT examinations occurred in patients with temporal lobe epilepsy. The calculated lower bounds for the costs of case finding for these groups were $4,363, $500 and $1,846/patient, respectively.