The present study aimed to determine the ability of two diet quality scores to predict the incidence of type 2 diabetes in women. The study population comprised a nationally representative sample of 8370 Australian middle-aged (45-50 years) women participating in the ALSWH (Australian Longitudinal Study on Women's Health), who were free of diabetes and completed FFQ at baseline. The associations between the Australian Recommended Food Score (ARFS) and Dietary Guideline Index (DGI) with type 2 diabetes risk were assessed using multiple logistic regression models, adjusting for sociodemographic characteristics, lifestyle factors and energy intake. During 6 years of follow-up, 311 incident cases of type 2 diabetes were reported. The DGI score was inversely associated with type 2 diabetes risk (OR comparing the highest with the lowest quintile of DGI was 0·51; 95% CI 0·35, 0·76; P for trend=0·01). There was no statistically significant association between the ARFS and type 2 diabetes risk (OR comparing the highest with the lowest quintile of ARFS was 0·99; 95% CI 0·68, 1·43; P for trend=0·42). The results of the present prospective study indicate that the DGI score, which assesses compliance with established dietary guidelines, is predictive of type 2 diabetes risk in Australian women. The risk of type 2 diabetes among women in the highest quintile of DGI was approximately 50% lower than that in women in the lowest quintile. The ARFS was not significantly predictive of type 2 diabetes.