The GHQ-12 is a widely used instrument designed to screen for psychological disturbance (defined as the inability to carry out normal psychological functions and/or the emergence of new distressing phenomena), in a wide variety of clinical groups. The Chinese version of the GHQ-12 is widely used in Hong Kong to screen women during pregnancy and in the postnatal period. The underlying factor structure of the GHQ-12 has been extensively investigated and there is strong evidence to suggest that the instrument is multi-dimensional. The current investigation explored the psychometric properties of this instrument using confirmatory factor analysis, logistic regression and reliability analysis in Chinese women during the third trimester of pregnancy and in the postnatal period. Two- and three-factor models offered superior fit to the data compared to the presumed uni-dimensional structure. However, a four-item sub-scale from an eight-item two-factor model was found to be a significant antenatal predictor of postnatal GHQ-12 assessed caseness. Further evaluation of the clinical utility of this specific two-factor model is recommended.