Background: Many patients with breast cancer work for pay at time of diagnosis, and the treatment plan may threaten their livelihood. Given rapidly evolving policies, evidence, and treatment options, we evaluated work experiences in a contemporary population-based sample of breast cancer patients to inform initiatives to reduce the burden of cancer care. Methods: We surveyed women aged 20-79 years diagnosed with stages 0-II breast cancer as reported to the SEER registries of Georgia and Los Angeles in 2014-15. Of 3672 eligible women, 2502 responded (68%); we analyzed 1006 who reported working prior to diagnosis. Multivariable models evaluated correlates of missing > 1 month and stopping work altogether vs missing ≤1 month. Results: In this diverse sample (48% white, 19% black, 20% Latina, 11% Asian), most pts (62%) received lumpectomy; 16% had unilateral mastectomy (8% with reconstruction); 23% had bilateral mastectomy (19% with reconstruction). One third (33%) received chemotherapy. The vast majority (84%) worked full time at diagnosis, but only 50% had paid sick leave, 39% disability benefits, and 38% flexible work schedules. Surgical treatment was strongly associated with missing > 1 month of work (OR 7.8 for bilateral mastectomy with reconstruction vs lumpectomy) and with stopping altogether (OR 3.1 for bilateral mastectomy with reconstruction vs lumpectomy). Chemotherapy receipt (OR 1.3 for missing > 1 month; OR 3.9 for stopping altogether) and race (OR 2.0 for missing > 1 month and OR 1.7 for stopping altogether, blacks vs whites) also correlated. Those with paid sick leave were less likely to stop working (OR 0.5), as were those with flexible schedules (OR 0.3). Those with disability benefits were more likely to stop working (OR 1.6) or miss > 1 month of work (OR 2.7). Conclusions: Working patients who received more aggressive treatments, particularly surgery, were much more likely to experience substantial employment disruptions. Given the growing choice of bilateral mastectomy by patients seeking peace of mind, particularly among young women with years of potential employment ahead, these findings suggest the importance of discussing impact of treatment decisions on employment. Funded by NCI P01CA163233.