Cancer as a dreadful disease has a relentless, very painful and debilitating curse and if not treated properly in time, results in death. Breast cancer is the most commonest cancer in women in India. The magnitude of cancer problem is increasing day by day. Breast Cancer, is a malignant growth of breast tissue. Breast cancer is the 3rd most common cancer in the world. In India breast cancer is the 2nd leading cancer in female. American Cancer Society estimates that 1.7 million new cases of invasive breast cancer will be diagnosed in 2014 about 40,910 breast cancer deaths are expected in 2007. Breast self examination is a procedure performed by an individual to physically and visually examine herself for changes in the breast under arm areas of the body. Breast self examination is an important of component health promotion and maintenance. Providing education and encouraging the women to perform breast self examination is recommended to decrease the mortality rates from breast disorders. Thus, this study aimed to assess the effectiveness of structured teaching programme on breast self examination among group IV staffs working at Sree Balaji Medical College and Hospital, Chrompet, Chennai -44. The main purpose of the study was to assess the knowledge among group IV staffs before and after the teaching programme, to assess the effectiveness of structured teaching programme among group IV staffs on breast self examination and to associate the post test knowledge score with the demographic variables. The study method was evaluative research approach and a pre experimental one group pre test and post test research design was used. Non randomized sampling technique was used to select the sample. The total sample was 30 group IV staffs. Pre test and post test scores was assessed by using structured questionnaires. The result of the study concluded that mean and standard deviation of knowledge level score in pre test was 3.8 and 1.76 and post test score was 12.5 and 2.24 the calculated ‘t’value was 21.75 which reveals that there was statistically highly significant difference between the pre test and post test at P<0.05. It is evidenced that the structured teaching programme was significantly effective in improving knowledge regarding breast self examination (BSE) among school teachers. Hence, the structured teaching programme regarding breast self examination among grade IV staffs is found effective.