Numerous studies have found that increased body size (weight or body mass index) is a risk factor for breast cancer development, recurrence, and death. The detrimental relationship between body size and breast cancer recurrence may be more pronounced among women with estrogen receptor (ER)/progesterone receptor (PR)-negative breast cancer. Considering the limited availability of treatments, and the association between body size and recurrence, alternative treatments are needed for ER/PR-negative breast cancer survivors, particularly overweight survivors. The objective of this pilot study was to examine the feasibility of a 12-week, multi-component meal-replacement weight loss intervention among overweight or obese ER/PR-negative breast cancer survivors; and to obtain preliminary data on changes in anthropometrics, biomarkers, and health-related quality of life (QOL). The 12-week intervention included a portion-controlled diet (including meal replacements) and a multi-component intervention (including behavioral techniques, diet modification, physical activity, and social support). The goal of the intervention was to help participants lose 5% or more of their initial weight by reducing their caloric intake and increasing their physical activity (to at least 15 minutes each day). Paired t-tests assessed changes in continuous measures. Body weight was measured weekly and mixed-model regression analysis assessed change in weight over time. Nineteen ER/PR-negative breast cancer survivors with a mean age of 59 years participated in the study. All but two of the participants completed the 12-week intervention. Women lost an average of 6.3 ± 4.9 kg ( P < 0.001), equivalent to 7.5% of their baseline weight. There were significant reductions in waist circumference ( P = 0.001), percent fat mass ( P < 0.001), total cholesterol ( P = 0.026), and triglycerides ( P = 0.002); and improvements in health-related QOL ( P = 0.017). Findings suggested that a meal-replacement weight loss approach among ER/PR-negative breast cancer survivors was feasible and was well received.