Stigma is a serious impediment to the well-being of those who experience it. Many family- caregivers are challenged by the stereotypes and prejudice that result from misconceptions about bipolar disorder.The purpose of this study was to explore the stigma experienced by family caregivers of patients with bipolar disorder.This was a qualitative and phenomenological study. In this study, we selected the family caregivers of patients with bipolar disorder in a psychiatric hospital (Iran) using purposive sampling in 2011. By reaching data saturation, the number of participant was 12. Data were gathered through in-depth interviews and analyzed by the "Collaizi" method.Stigma was a pervasive concern to almost all participants. Family caregivers of patients with Bipolar disorders reported feelings and experiences of stigma and were most affected by them. Analysis of the interviews revealed 3 themes: Negative judgment, Shame, Stigmatization and Social Isolation.For a person with bipolar disorder, this illness is associated with the following problems: worse recovery, difficulty accessing health services, receiving poor treatment and support, and difficulty gaining community acceptance. Rejection of people with mental illness might also affect their family caregivers at various levels.