The Evaluation of patients complaining of psychiatric symptoms following head injury is much affected by the results of various tests. The objecive of this paper is to investigate the effectiveness of each lest by comparing the structual and fuctional brain studies. The subjects were 93 organic menial disorder in and out patients at the Dept. of Neuropsychiatry of the Kyung Hee University Hospital. After carrying out MRI, CT, SPECT, EEG, the results of each were analysed for the sesitivity and ability to detect focal lesion. The degree of inter-test correlations of lest results were also investigated. Furthermore, the characteristic features of psychological tests were studied and the relationship between each of above mentioned tests and psychological test was examined. As for the test sensitivity to diagnosis, the SPECT was the most superior followed by MRI, CT, EEG in thai order. In the case of abnormality, SPECT ranked 1st in detection of focal lesion, followed by MRI, CT in that order. In the inter-test result correlation, the correlation of SPECT-MRI was statistically significant. When mare than moderate abnormality EEG finding was reported, it correlated significantly with that of MRI findings. In the MMPI, the average scores on F, Hs, D, Hy, Pa, Pt, Sc subscales were above 60. Abnormal SPECT group scored significantly high on the F, Pd, Pa, Sc, Ma scales and therefore in comparison ot the SPECT normal group, displayed more psychotic features. In K-WAIS, the mean full scale IQ was down to 77. 23(Verbal IQ : 78.76, Performance IQ : 77.44) but there was no characterogic significant relationship between the lowered to and abnormal SPECT, MRI, CT and EEG results. In conclusion, 1) The SPECT was mast superior in sensitivity and detection of focal lesions. In comparision with other tests, the results of SPECT correlated well with MRI had thus is thought to be very usefull testing method in the evaluation of organic mental disorder patients. 2) The MRI had relatively high sensitivity, ability to detect focal lesion and superior correlation with other test. 3) Although EEG fared less an sensitivity in comparison to other tests, the results of above moderate abnormal grade group and that of MRI correlated significantly. 4) In the MMPI highly scored in F, Hs, D, Hy, Pa, Pt, Sc subscales and abnormal SPECT patients were shown to display more sever psychotic features. There was no significant character relationship between the lowered IQ(in K-WAIS) and abnormal findings on MRI, CT, SPECT, EEG.