A review of information from the New Mexico Tumor Registry on women diagnosed as having primary breast cancer from 1969 through 1985 revealed temporal changes in the surgical treatment of this disease. After 1980 the percentage of women receiving breast-conserving surgery for local-stage disease increased from 6% to 25%. Most surgeons performing operations for breast cancer had not performed a breast-conserving operation before 1981 but had used this procedure at least once in the period from 1981 through 1985. Women younger than 50 years or older than 80 years were most likely to undergo this procedure. In that period, radiotherapy after breast-conserving surgery could not be documented for 26% of the women 65 years old or younger or for 56% of the women aged 65 years or older. Thus, there has been a marked shift in New Mexico in the surgical approach to local-stage breast cancer in the 1980s. This shift involved most surgeons treating the disease and included women of all age groups. The apparent lack of adjuvant radiotherapy in some women receiving conservative surgeries may prove to be a deleterious consequence of this change in surgical management.