To examine self-reported severity of fatigue and disturbed sleep experienced daily by women with breast cancer during multiple cycles of chemotherapy, exploring potential classes of women experiencing similar symptom trajectories. .

In a secondary analysis, classes of women experiencing similar patterns of fatigue and disturbed sleep were identified. .

Oncology clinics in the United States. .

166 women with breast cancer receiving chemotherapy. .

Severity scores were self-reported daily using an automated system. Classes of fatigue and disturbed sleep severity were identified using latent growth mixture modeling. .

Fatigue, disturbed sleep, age, stage of disease, education, employment, marital status, chemotherapy regimen, hours lying down, and missed work. .

Three fatigue classes were identified.

Patterns of symptom trajectories for fatigue and disturbed sleep were distinguished by baseline symptom severity. .

Identification of women at risk for fatigue and disturbed sleep may allow clinicians to intensify symptom management.