Within the Italian Breast Screening Network, individual data are collected yearly on about 50% of all screen-detected operated lesions. In 2003 results showed a good overall quality of diagnosis and treatment, and an improving trend over time. Critical issues were identified in the number of cancers diagnosed pre-operatively, which is still below standards, and in the waiting times for surgery. Compliance with recommendations as to not performing frozen section on small lesions and unnecessary axillary dissection for ductal carcinoma in situ still have not reached the target. The sentinel lymph node technique was performed on the axilla in more than 60% of screen-detected invasive cancers, avoiding a large number of potentially harmful dissections. Preliminary data for 2004 show further progress towards better quality, particularly in pre-operative diagnosis and in the avoidance of frozen section. The detailed results of this survey have been distributed to local and regional screening programmes in order to allow multidisciplinary discussion and the identification of appropriate solutions to any problems documented by the data. Specialist Breast Units with adequate case volume would provide the best setting for making audit effective in producing quality improvement.