Up to 40% of women experience dissatisfaction after breast reconstruction due to unexpected outcomes that are poorly aligned with personal preferences. Identifying what attributes patients value when considering surgery could improve shared decision-making. Adaptive choice-based conjoint (ACBC) analysis can elicit individual-level treatment preferences. To identify which attributes of breast reconstruction are most important to women considering surgery and to describe how these attributes differ by those who prefer flap vs implant reconstruction. This web-based, cross-sectional study was conducted from March 1, 2022, to January 31, 2023, at Duke University and between June 1 and December 31, 2022, through the Love Research Army with ACBC analysis. Participants were 105 women at Duke University with a new diagnosis of or genetic predisposition to breast cancer who were considering mastectomy with reconstruction and 301 women with a history of breast cancer or a genetic predisposition as identified through the Love Research Army registry. Relative importance scores, part-worth utility values, and maximum acceptable risks were estimated. Overall, 406 women (105 from Duke University [mean (SD) age, 46.3 (10.5) years] and 301 from the Love Research Army registry [mean (SD) age, 59.2 (11.9) years]) participated. The attribute considered most important was the risk of abdominal morbidity (mean [SD] relative importance [RI], 28% [11%]), followed by chance of major complications (RI, 25% [10%]), number of additional operations (RI, 23% [12%]), appearance of the breasts (RI, 13% [12%]), and recovery time (RI, 11% [7%]). Most participants (344 [85%]) preferred implant-based reconstruction; these participants cared most about abdominal morbidity (mean [SD] RI, 30% [11%]), followed by the risk of complications (mean [SD], RI, 26% [11%]) and additional operations (mean [SD] RI, 21% [12%]). In contrast, participants who preferred flap reconstruction cared most about additional operations (mean [SD] RI, 31% [15%]), appearance of the breasts (mean [SD] RI, 27% [16%]), and risk of complications (mean [SD] RI, 18% [6%]). Factors independently associated with choosing flap reconstruction included being married (odds ratio [OR], 2.30 [95% CI, 1.04-5.08]; P = .04) and higher educational level (college education; OR, 2.43 [95% CI, 1.01-5.86]; P = .048), while having an income level of greater than $75 000 was associated with a decreased likelihood of choosing the flap profile (OR, 0.45 [95% CI, 0.21-0.97]; P = .01). Respondents who preferred flap appearance were willing to accept a mean (SD) increase of 14.9% (2.2%) chance of abdominal morbidity (n = 113) or 6.4% (4.8%) chance of complications (n = 115). This study provides information on how women value different aspects of their care when making decisions for breast reconstruction. Future studies should assess how decision aids that elicit individual-level preferences can help tailor patient-physician discussions to focus preoperative counseling on factors that matter most to each patient and ultimately improve patient-centered care.