To describe therapy and changes in therapy over time for women diagnosed with ductal carcinoma in situ (DCIS) and treated in the community setting. Women aged 20 or older diagnosed with DCIS in this study were sampled from the population-based Surveillance, Epidemiology and End Results Program. A total of 770, 1055, 480, and 404 women with DCIS were selected in 1991, 1995, 2000, or 2005, respectively. Most women do not have nodal sampling, but between 2000 and 2005 there was an increase in the use of sentinel node biopsy, 9 and 22%, respectively. Of the DCIS patients, 80% had no or unknown HER-2 assays, 12% were postitive, 7% negative, and 1% equivocal. After adjusting for tumor size, age, race, marital status, and insurance there has been a decrease in mastectomy since 1991. Of women with DCIS 36% were given tamoxifen in 2000; in 2005 this decreased to about 21%. However, in 2005 we see the use of aromatase inhibitors in nearly 4% of patients. HER-2 testing is increasingly performed for women with DCIS. Despite positive HER-2 tests no women received trastuzumab as of 2005. Despite the lack of clinical trials evidence, aromatase inhibitors are being prescribed for women with DCIS.