Background:　Few　studies　have　investigated　the　association　between　body　mass　index　(BMI)　and　breast　cancer　with　consideration　to　estrogen/progesterone/human　epidermal　growth　factor　type　2　receptor　status　(ER/PR/HER2)　in　the　breast　tissue　among　Chinese　pre-　and　post-menopausal　women.　Methods:　Four　thousand　two　hundred　and　eleven　breast　cancer　patients　were　selected　randomly　from　seven　geographic　regions　of　China　from　1999　to　2008.　Demographic　data,　risk　factors,　pathologic　features,　and　biological　receptor　status　of　cases　were　collected　from　the　medical　charts.　Chi-square　test,　fisher　exact　test,　rank-correlation　analysis,　and　multivariate　logistic　regression　model　were　adopted　to　explore　whether　BMI　differed　according　to　biological　receptor　status　in　pre-　and　post-menopausal　women.　Results:　Three　thousand　two　hundred　and　eighty　one　eligible　cases　with　BMI　data　were　included.　No　statistically　significant　differences　in　demographic　characteristics　were　found　between　the　cases　with　BMI　data　and　those　without.　In　the　rank-correlation　analysis,　the　rates　of　PR+　and　HER2+　were　positively　correlated　with　increasing　BMI　among　post-menopausal　women　(r(s)　(BMI,)　(PR+)　=　0.867,　P　=　0.001;　r(s)　(BMI,)　(HER2+)　=　0.636,　P　=　0.048),　but　the　ER+　rates　did　not　vary　by　increasing　BMI.　Controlling　for　confounding　factors,　multivariate　logistic　regression　models　with　BMI＜24　kg/m(2)　as　the　reference　group　were　performed　and　found　that　BMI　＞=　24　kg/m(2)　was　only　positively　correlated　with　PR+　status　among　post-menopausal　breast　cancer　cases　(adjusted　OR　=　1.420,　95%　CI:　1.116-1.808,　Wald　=　8.116,　P　=　0.004).　Conclusions:　Post-menopausal　women　with　high　BMI　(＞=　24　kg/m(2))　have　a　higher　proportion　of　PR+　breast　cancer.　In　addition　to　effects　mediated　via　the　estrogen　metabolism　pathway,　high　BMI　might　increase　the　risk　of　breast　cancer　by　other　routes,　which　should　be　examined　further　in　future　etiological　mechanism　studies.