Objective: post partum breast inflammation occurs in 9,5% of feeding women. It can involve connective tissue between glandular and ductal structures (cellulitis) or glandular structures (adenitis). The standard antibiotic therapy in 10% of cases becomes unsuccessful and usually ends with an abscess formation. The aim of our study was to find out if US examination can help in diagnostics of inflammatory process and in differentiation this lesions with other possible pathologies. Material and method: since January 2007 up to May 2008 in 155 woman the clinical signs of inflammation of the feeding breast were found. The immediate antibiotic therapy was completely unsuccessful in 43 (27,7%) of them. All of these patients were referred to US lab. US examination was performed with Voluson 730 Expert (GE) machine and linear 5-16 MHz probe. Results: US examination revealed 17 cases of local oedema – cellulitis, 10 – local ductal widening with thick fluid contents, 9 – abscesses , 4 – inflammatory cysts, 1 – inflammatory carcinoma, 2- without sonographic signs of inflammation in breast. All results were confirmed with either clinical follow-up or by surgery. Conclusions: 1. US can diagnose the presence of abscess, 2. It can help to differentiate the other type other type of lesions within feeding breast 3. The results of US findings can be helpful in further decision of therapy