Fatigue is both a symptom and a predictor of depression in women after childbirth. At the same time, postpartum fatigue is experienced by most non-depressed women. Health care providers experientially know that not all women who experience postpartum fatigue will manifest depression. However, while researchers agree that fatigue and depression are distinct concepts, they have not yet identified a means for describing or measuring this distinctness. A new model proposing how fatigue may be differentiated from depression after childbirth is presented. The Depressive Symptoms Responsiveness Model proposes that depression-related postpartum fatigue may potentially be differentiated from non-depression-related postpartum fatigue on the basis of whether depressive symptoms abate when fatigue is relieved. The ability to differentiate between fatigue and depression in postpartum women has the potential to improve women's health through improvements in practice and resource utilization. Furthermore, differentiation may lead to a better understanding of the role of fatigue in postpartum depression.