Complementary and alternative medicine (CAM) use is increasing worldwide. However, there have been few theoretical models established to exploring psychosocial factors of CAM use. This study attempted to examine the potential for extending the Transtheoretical Model (TTM) to the area of CAM use. For this purpose, a hypothesized structural equation model of readiness of general CAM use was established based upon the literature. The model consisted of key constructs of the TTM which had been specific to CAM use and indicated the hypothesized relationships between key constructs. The purposes of this study were to 1) test the theory-based model use using structural equation modeling technique; 2) examine hypothesized relationships among key constructs from the TTM; 3) improve model fit by modifying the pathways between the model constructs in a theoretically sensible way, and 4) test whether the relationships among the constructs differ across subgroups of gender and ethnicity. The research was a secondary analysis of survey data (n=518) taken from a study of complementary medicine use among Australian university students in 2000. Results: overall, the hypothesized structural model showed a satisfactory degree of fit to the observed data. Four conclusions of direct, significant relationships were drawn: 1) processes of change showed positive effects on stages of CAM use; 2) processes of change showed positive impacts on pros; 3) processes of change showed negative impacts on cons; and 4) cons showed negative effects on self-efficacy. Pros and cons were significantly and negatively correlated with each other. Conclusion: The finding of this study provided quantitative evidence of the applicability of the TTM to CAM use. The key constructs from the TTM substantially influenced the readiness of CAM use and explained the decisional making processes of CAM use among Australian university students.