There have been suggestions that some self-administered questionnaires designed to assess psychiatric disorder tend to overestimate prevalence in samples from Latin America. This phenomenon may be obscured when the General Health Questionnaire (GHQ) is used, as it is recommended that researchers determine the threshold in each setting by comparing the GHQ with a standardised interview. Reports in the literature suggest that Latin American samples have a higher threshold for case definition using the GHQ than that found in British samples. The present study confirmed this finding when comparing the 12-item GHQ in a Chilean primary care sample with a sample of primary care attenders from the United Kingdom. The increase in GHQ scores in the Chilean sample persisted after adjustment for age, sex, marital status and the score on the Revised Clinical Interview Schedule (CIS-R). The increase in scores seen in the Chilean sample was only found in that half of the GHQ that asks about negative aspects of mental health.