To evaluate the feasibility of in vivo measurement of the fatty acid (FA) composition of breast adipose tissue by MRS on a clinical platform. MRS experiments were performed at 3 T, using a STEAM sequence, on 25 patients diagnosed with breast cancer. MR spectra, acquired on healthy breast tissue, were analysed with the LCModel. The measured values of the saturated fatty acid (SFA), mono-unsaturated fatty acid (MUFA) and poly-unsaturated fatty acid (PUFA) fractions were 23.8 ± 7.1%, 55.4 ± 6.8% and 20.8 ± 4.4%, respectively. The values of SFA, MUFA and PUFA observed in the current study are in the same range as those found in two previous studies performed at 7 T. The results of the current study show that it is possible to quantify the fatty acid composition of breast tissue in vivo in a clinical setting (3 T).