Dysregulation of lipid metabolism is common in cancer. Lysophosphatidylcholine acyltransferase 1 (LPCAT1) has been implicated with various cancer types. Here we analyzed by immunohistochemistry its expression in 2,197 breast cancers. LPCAT1 staining was found in 97.8% of 1,774 interpretable tumors, including 48.1% with weak, 28.7% with moderate, and 14.4% with strong expression. The frequency of LPCAT1 positivity depended on the histological tumor type. Moderate or strong LPCAT1 positivity was more common in cancers of no special type (NST) (46.2%) than in lobular carcinomas (25.9%; p<0.0001). Strong LPCAT1 was associated with BRE grade, tumor cell proliferation and overall survival in all cancers and in the subgroup of NST cancers (p<0.0001, each). In the subset of NST cancers the prognostic effect of LPCAT1 expression was independent of pT, and BRE grade (p<0.0001 each). A comparison with molecular features showed that LPCAT1 was strongly associated with estrogen receptor negativity (p<0.0001), progesterone receptor negativity (p<0,0001), amplification of HER2 (p<0.0001) and MYC (p=0.0066), as well as deletions of PTEN (p<0.0001) and CDKNA2 (p=0.0151). It is concluded that LPCAT1 overexpression is linked to adverse tumor features and poor prognosis in breast cancer. These data also highlight the important role of lipid metabolism in breast cancer biology.