In recent years, MR mammography has gained increasing importance in breast diagnostics. The main advantage of this technique is its high sensitivity for invasive breast cancer. The two main indications for MR mammography are preoperative staging of breast cancer and the differentiation between postoperative changes and recurrent tumor. In addition, MR mammography is increasingly used for problem solving in cases of questionable clinical, mammographic or sonographic findings. At this it is important to know not only the different manifestations of breast cancer, but also important benign and malignant diagnostic alternatives. Furthermore, it is necessary to be familiar with therapy-related changes. The most important criterion to differentiate between benign and malignant lesions in MR mammography is the extent and temporal course of contrast enhancement. in addition, the lesion morphology and the signal intensity on T-2-weighted images can be used to distinguish between different disease entities. The following review article will discuss typical and unusual findings in breast MRI, including rare entities as well as changes after breast conserving therapy and chemotherapy.