We report the cases of three patients with subdural hematoma following minor closed-head trauma in whom the initial neurologic examinations and cranial computed tomography (CT) scans were normal. In each case, the patient was re-evaluated clinically several times (average of four times) due to persistence of post-traumatic symptoms. The development of focal neurologic signs, which eventually led to a correct diagnosis, was significantly delayed in all three cases (average of 47 days). All three patients had large subdural hematomas requiring surgical drainage. The timely diagnosis of subdural hematoma may be difficult despite the appropriate use of CT scan in the immediate post-traumatic period. Repeat CT scan may be indicated in patients suffering minor head trauma with persistent symptoms. These patients seem to recover without deficit following neurosurgical treatment despite a significant delay in diagnosis.