Although breast self-examination (BSE) continues to be recommended as an adjunct to clinical screening techniques for the early detection of breast cancer, little is known about events that might negatively influence long-term adherence. The primary aim of this investigation was to determine if regularity of BSE would decline after a benign breast biopsy. Analyses are based on 655 women: 83 women who self-discovered the breast problem by BSE, 179 women in whom the problem was discovered by the health care system, and a control group of 393 women who had no history of breast problems. Frequency of BSE was assessed over two six-month periods and collapsed into three categories--nonpractitioner, irregular practitioner, and regular practitioner. Results indicated that the percentage of women in the self-discovered group who reported decreased regularity of BSE was over three times higher than that found in the control group. The largest percentage increase in BSE frequency was evidenced by the health care-discovered group. Logistic regressions revealed that the biopsy experience was a more powerful indicator of subsequent BSE practice than either sociodemographic characteristics or whether one engaged in other preventive health behaviors. The data provide substantial evidence that a benign biopsy can affect BSE practice, with the direction and magnitude of the change influenced by mode of discovery of the breast problem, perceived degree of confidence in ability to perform BSE, and level of practice before the biopsy. Postbiopsy educational strategies incorporating these findings and targeted at specific subgroups are outlined.