The aim of the present review was to examine objective and subjective burdens in primary caregivers (usually family members) of patients with bipolar disorder (BD) and to list which symptoms of the patients are considered more burdensome by the caregivers. In order to provide a critical review about caregiver's burden in patients with bipolar disorder, we performed a detailed PubMed, BioMedCentral, ISI Web of Science, PsycINFO, Elsevier Science Direct and Cochrane Library search to identify all papers and book chapters in English published during the period between 1963 and November 2011. The highest levels of distress were caused by the patient's behavior and the patient's role dysfunction (work, education and social relationships). Furthermore, the caregiving role compromises other social roles occupied by the caregiver, becoming part of the heavy social cost of bipolar affective disorder. There is a need to better understand caregivers' views and personal perceptions of the stresses and demands arising from caring for someone with BD in order to develop practical appropriate interventions and to improve the training of caregivers.