In vivo magnetic resonance spectroscopy (MRS) is a rapidly evolving clinical tool for diagnosis, characterization, and monitoring of the therapeutic response of breast pathologies. Many in vivo studies reported a peak at 3.2 ppm corresponding to choline-containing metabolites (tCho) as a reliable biochemical marker of malignancy. However, the detection of tCho in normal and benign breast tissues led to the development of in vivo absolute quantification of tCho concentration to define a cutoff value for the differentiation of normal, benign, and malignant breast tissues. The major limitation of in vivo MRS is in examining small lesions, which thus limits its clinical utility. However, in larger lesions, it has the potential to replace the biopsy procedure. Many reports have shown that addition of MRS to magnetic resonance imaging (MRI) increases the specificity of diagnosis. Several in vitro and ex vivo MRS studies have also shown that alterations in choline-containing metabolites are associated with malignant transformation and, in addition, have provided comprehensive metabolic profiles giving insight into the underlying biochemistry of cancer. This article reviews the developments of breast MRS and its role in diagnosis and treatment management.