Objective: To conduct a systematic review of the literature about the symptom of rumination in bipolar disorder (BD). Methods: We searched the MEDLINE (PubMed), ISI Web of Knowledge, PsycINFO, and SciELO databases using the descriptors “rumination” and “bipolar disorder” and no time limits. This strategy yielded 105 references, of which 74 were selected. Inclusion criteria were studies involving patients with BD and the use of at least one validated scale for the assessment of rumination. Review articles were excluded. Seventeen articles were ultimately analyzed and included in the review. Results: Rumination is present in all BD phases, is a stable interepisodic symptom, is associated with symptoms of depression, anxiety, and hypomania, and may occur in response to both positive and negative affect. There is no research on rumination and neurobiological findings in patients with BD. Conclusions: Rumination seems to be independent of mood state, but shows close relationship with it. It is possible that rumination has a negative impact on cognitive and executive functions, particularly inhibitory control. Finally, rumination is an important symptom in both phases of BD, and, therefore, may be a useful target for further exploration as a dimensional domain and a transdiagnostic phenomenon in Research Domain Criteria (RDoC) projects.