In addition to discussing effectiveness of breast cancer screening initiated within the National Public Health Programme, the problem of how to treat non-palpable, early invasive and in situ breast cancer (DCIS) is considered. The theoretical issue of the sentinel lymph node and its impact on biopsy practice have also been dealt with. In the authors' region, screening was introduced in 1999 and after a short break has been continued since 2002. Patient data of three periods, each of two years, each with ten years' interval (1982-1983, 1992-1993, 2002-2003) have been analysed. Changes in the number of surgical operations and tumour size, incidence of in situ cancer, lymph node involvement and distribution of types of surgery have been studied. Biopsy of the sentinel lymph node has been applied since May, 2003 (with 45 biopsies performed until 31 December, 2004). The number of persons participating in the screening programme has gradually increased, the number of surgical operations because of breast cancer increased from period to period. Size of the detected tumours has decreased, the percentage of non-palpable cases has been significant (445 surgical interventions during the years 2002-2004: surgery: 19%). The proportion of DCIS has increased to nearly four times as compared to data of years immediately preceding the era of screening (1993-1998: 11 cases, 2%; 1999-2004: 62 cases, 7.5%). Specificity of sentinel lymph node biopsy was 90%, with a sensitivity of 65%. The proportion of breast saving surgery has increased above 50%. The authors regard screening as successful, in their opinion, its benefits cannot be questioned, in spite of some controversial issues. As to the treatment of non-palpable, early invasive cancer, they underline the importance of preoperative evaluation--cytology, core biopsy--and establishing dignity. The issues of localisation--wire hook marking--and histological processing--large blocks--have also been dealt with. In spite of the fact that the risk for potential malignancy of DCIS lesions has not yet been fully clarified, adequate treatment is indicated; the authors take stand on the issues of indication for surgery, postoperative radiotherapy and use of Tamoxifen. Indications and contraindications of sentinel lymph node biopsy have been summed up.