Because of its technical capabilities, its rapidity and its non-invasive nature, computed tomography (CT) has given a new scope to neurological diagnosis and to the understanding of various aspects of neurological science. The availability of this test is determined by the patient load. If precise clinical indications are not considered, patients requiring CT the most may be denied immediate examination because less urgent cases may be occupying valuable diagnostic time. Moreover, the test is relatively expensive for the individual patient and for the community; this presents another facet of its use that should be taken into account. The technical limitations and clinical priorities to be considered when a physician is entertaining this test for a patient have been outlined. The indications have been divided into absolute and relative, according to the degree of clinical urgency. As a result, a priority guideline for diagnostic CT has been provided.