In order to investigate the organic and psychogenic components of post-concussive syndrome (PCS), the subjective complaints, the cognitive findings and the Minnesota Multiphasic Personality Inventory (MMPI) profiles of 53 consecutive mild head injury patients (MHI) with persistent PCS were evaluated. The results seem to suggest the presence of two groups: in the first, minimal lesional signs were associated with more prolonged loss of consciousness (LC) and post-traumatic amnesia (PTA), as well as an MMPI profile not indicative of a neurotic state, whereas in the second the absence of any lesional sign was associated with shorter LC and PTA duration, as well as evidence of neurotic MMPI scores. A female prevalence was observed in the first group and a male prevalence in the other one.