The aim of the study was evaluation of interventional ultrasound in the diagnostics of changes after conservative surgical treatment for early breast carcinoma and in the therapeutic removal of postoperative seromas. The analysis of USG- and bioptic findings in 240 breast cancer patients after conservative breast surgery performed between 1996-1998 is reported. The major findings were: postoperative scars, granulomas, seromas, hematomas, fat necrosis, skin thickening, inflammatory changes and local tumor recurrence. In our experience, the interventional ultrasound coupled with cytological examination are reliable methods for the follow up of early and late postoperative changes with sufficient degree of correlation between USG- and histologic findings.