There is much debate on the nature and duration of cognitive deficits and postconcussive symptoms (PCS) after mild head injury. Most studies performed so far have compared head-injured patients with subjects who had not suffered a concussion, instead of directly comparing patients with and without persistent PCS. The present study examined whether patients with PCS (n = 9) about 6 months after an uncomplicated mild head injury performed less well on selected neuropsychological tests than patients with mild head injuries who did not have PCS (n = 9) and healthy controls (n = 9). Patients with PCS were individually matched with controls for the time elapsed after the injury, age, sex, and education. We found that patients with PCS performed less well on tests of divided and selective attention than both patients without PCS and healthy controls. It is concluded that cognitive deficits may be present up to 6 months after mild head injury when symptoms persist. The findings indicate that patients with mild head injury and subjective symptoms may manifest demonstrable cognitive deficits.