This study examined the vulnerability of several self-report instruments commonly used in neuropsychological evaluation - the Iowa Interview for Partial Seiwre-Like Symptoms, Postconcussion Checklist (PCL). Postconcussion Syndrome Checklist (PCSC), and Beck Depression Inventory (BDI) - to exaggerated or feigned complaints. Two hundred twenty-nine college student volunteers completed the instruments under one of three conditions: I) Base Rate/Control; simulated Head Injured, but 2) without or 3) with prospect of financial gain for the injury. Although the simulated Head Injured groups did not differ significantly from one another, both groups endorsed more symptoms than the Base Rate group, suggesting that the instruments are vulnerable, to simulation. Base rates of head injury symptoms in the normal population, laypersons' knowledge about the sequelae of mild head injury, and implications of using symptom checklists in medicolegal evaluations were discussed, as was the desirability of replicating this study with noncollege student populations.