Background: Breast infarction can occur in benign breast lesions, such as fibroadenomas, as well as healthy breast tissue, typically in the gravid or lactating patient. Few theories, however, exist to explain this unusual lesion. Case Report: We present a very rare case of a 27-year-old female patient with extensive, multifocal, bilateral mammary infarction. A literature search was also performed to confirm its rarity. Although solitary or limited areas of spontaneous infarction have been documented, there are no documented cases where such a large, multifocal area of involvement has occurred without obvious explanation. Conclusion: Extensive multifocal post-partum breast infarction is a rare occurrence that has potential long-term effects. This should be considered when taking patient history in post-partum patients, as well as those with extensive calcifications on mammogram years after giving birth.