Background: Mastitis is an inflammation of the breast, with or without infection. It can be viewed as a continuum of disease, from non‐infective inflammation of the breast to infection that may lead to abscess formation. Nursing management is conducted to deepen patients’ understanding of their own diseases, enhancing their self-care ability, and establishing healthy living habits. Aim: Evaluate effect of a nursing teaching protocol on mastitis prognosis. Research design: A quasi-experimental research design was utilized. The study was conducted in the breast unit in general surgery department at Main Assiut University Hospital. A convenient sample of sixty adult female patients diagnosed with mastitis, their ages ranged between 20 to 65years old. Patients were divided equally into two groups thirty for each; both groups were assessed at base line using the following tools: An interview questionnaire sheet, mastitis self-care practices, numeric pain intensity scale, and mastitis prognosis sheet. The control group exposed to routine care and study group received mastitis teaching protocol. After three weeks; both groups were reassessed by the same tools. Results: A highly statistically significant improvement was found in the study group regarding their knowledge, practice, pain level and incidence of complications post-protocol implementation than control group who exposed to routine care with P-value <0.001**. Conclusion/Recommendations: Applying nursing teaching protocol to patients with mastitis significantly improved their prognosis/ distribution of the mastitis teaching protocol for female patients with mastitis based on their needs assessment to improve their outcomes.