We aimed to identify whether abdominal fat distribution could affect the outcome in metastatic breast cancer (MBC) patients treated with aromatase inhibitors (AIs) or not. A total of 42 MBC patients treated with first line hormonal therapy were enrolled in this study. Factors associated with overall survival in the univariate analysis were age, c-erb-B2 expression intensity (+++ versus others by immunohistochemistry), and WHR, whereas only WHR retained significance in the multivariate analysis. Median overall survival figures were 472 days versus unreached for patients with a WHR of <0.92 and >or=0.92 (Log rank statistic=9.76, P=0.002). Similarly, the corresponding progression free survival figures for patients with a WHR of <0.92 and >or=0.92 were 423 versus 1004 days (Log rank statistic=6.37, P=0.012). This study suggests that WHR may serve as a potential predictive marker in MBC patients treated with AIs.