Studies have suggested that family burden adversely affects clinical outcome in the major mental disorders. Logistic regression analysis was used to evaluate the effect of family burden reported at baseline (acute model), or 7 months (stabilization model), on the risk of having a subsequent affective episode, in a sample of 264 patients with Research Diagnostic Criteria-diagnosed bipolar illness. Higher levels of baseline burden and a depressive index episode significantly increased the risk for a major episode at 7 months. Higher 7-month burden significantly increased the risk for a major episode at 15 months among patients with relatively low 7-month BPRS symptom levels. Caregiver burden reported at times of symptom relapse and during stabilization predicts subsequent adverse clinical outcomes among patients with bipolar disorder and suggests a need for family support.