The purpose of this study was to examine the accuracy of translation and to test the validity of the Greek version of the General Health Questionnaire (GHQ). In the translation study, the English and the Greek versions of the GHQ were administered to a sample of 50 bilingual respondents. The internal consistency, item-by-item and the subject-by-subject analysis have shown that the 2 versions are equivalent and therefore the Greek translation is highly accurate. In the validity study, 100 consecutive patients attending an internal medicine outpatient clinic completed the Greek version of the GHQ-60 and were interviewed independently using the Present State Examination (PSE). The validity of the shorter forms of the questionnaire (GHQ-30 and GHQ-28) was tested by disembedding the relevant items from the larger set. The correlations obtained between the scores of the questionnaire and the PSE ratings, as well as all the validity indices (sensitivity, specificity, positive predictive value, negative predictive value and overall misclassification rate) were quite satisfactory for all the GHQ forms, thus confirming the validity of the questionnaire in its Greek version. The best cut-off points as found by receiver-operating characteristics analysis were 11/12 for the GHQ-60, 5/6 for the GHQ-30 and 4/5 for the GHQ-28. The revised (CGHQ) scoring system for the GHQ-30 has not been proved superior to the conventional scoring method. The above results are discussed in relation to the pertinent literature and especially the studies carried out in similar settings and in countries with similar cultural backgrounds.