Background: Women undergoing chemotherapy for breast cancer often experience side effects that can impact quality of life and tolerance of planned therapy. This can lead to poor outcomes. By understanding these changes, we can intervene and improve the treatment for women. We hypothesized that chemotherapy would be associated with changes in functional status and nutrition related symptoms in breast cancer survivors. Methods: Patients were prospectively recruited prior to initiation of their neo-adjuvant or adjuvant therapy. Body mass index (BMI) was abstracted from records. The patient’s functional status was assessed using the Duke Activity Status Index (DASI), and the Patient Generated Subjective Global Assessment (PG-SGA) characterized nutrition-related symptoms of patients. Participants completed these questionnaires prior to initiating the first cycle chemotherapy (time point 1), during the second cycle (time point 2), and during the last cycle of chemotherapy, 12-20 weeks after initiation of treatment (time point 3). Changes in BMI, functional status, and symptomatology were analyzed using linear mixed effects models. Results: Twenty-five women enrolled; 19 women with a median age of 51 (range 33-66) completed the study. There was no significant change in BMI (p = 0.18) over the duration of chemotherapy. Analysis of DASI data indicated that there was a significant decline in peak oxygen uptake (p = 0.005), showing a decrease in functional capacity from before the first cycle to both the second and the last cycles. This suggests that functional capacity dropped significantly once chemotherapy began and stayed below baseline. There was also a significant change in PG-SGA (p = 0.005), indicating significant reported nutrition-related symptoms. PG-SGA scores were significantly higher during the second cycle compared to the other two time points, indicating that patient’s showed the highest degree of symptoms shortly after initiation of treatment and then improved. Conclusions: Chemotherapy is associated with symptomatology and a decrease in functional capabilities. Improved understanding of symptom burden during chemotherapy will allow more specific interventions to be designed that can help improve quality of life.