Mucoepidermoid carcinomas are very rare breast tumors. The morphology of this breast tumour is similar to its counterpart in the salivary gland. The first two cases reported were low-grade and neither patient had metastatic disease. Furthermore, none of the five patients with low-grade mucoepidermoid carcinoma reported by Fisher had axillary lymph node involvement and were alive with no evidence of disease 4 to 10 years after diagnosis and were considered of probable favourable prognosis. A high grade form of mucoepidermoid cancer might occur in the breast as it does in the salivary gland. All high-grade variant cases published had demonstrable lymph node or distant metastases and rapidly fatal outcomes. This report describes a case of high-grade mucoepidermoid carcinoma of the breast with a disease-free interval of 5 years, despite of unfavourable histologic features at the time of diagnosis.