OBJECTIVES: Individuals with bipolar disorder (BD) experience a high degree of impairment that affects aspects of daily life including autonomy, relationships and employment. The Wide AmbispectiVE study of the clinical management and burden of bipolar disorder (WAVE-bd) aimed to describe functioning and quality of life (QoL) in a multinational BD cohort. METHODS: Multinational, multicenter, non-interventional, cohort study of patients diagnosed with BD-I or BD-II with ≥1 mood episode in the preceding 12 months (retrospective data collection) followed by a minimum 9 months’ prospective follow-up. Functioning was measured using the Functioning Assessment Short Test (FAST) tool (score range: 0-72, higher score indicates worse functionality, results presented from initial visit). QoL was measured with the EuroQoL-5D visual analogue scale (VAS) tool (score range: 0-100, higher score indicates better health), and the EQ-5D Index (score range: 0-1, higher score indicates better health) at every visit during the study. RESULTS: Overall, 2,896 patients were included in the analysis (1,989 BD-I, 907 BD-II).  FAST total scores (mean±SD) for BD-I and BD–II patients, respectively, were 50.1±17.2 and 48.8±16.5. QoL fluctuated with disease phase; in BD-I patients the EQ-5D VAS scores (mean±SD) were 71.9±18.3 in hypomania, 70.4±18.7 in euthymia, 69.6±22.8 in mania, 56.5±18.5 in mixed episodes, and 53.5±22.0 in depression. In BD-II patients, EQ-5D VAS scores were 72.1±18.7 in hypomania, 70.0±17.8 in euthymia and 54.2±20.2 in depression. EQ-5D Index scores (mean±SD) reflected a similar trend (BD-I: hypomania 0.70±0.28, mania 0.67±0.29, mixed episodes 0.53±0.28, depression 0.49±0.29, euthymia 0.41±0.27; BD-II: hypomania 0.65±0.27, depression 0.46±0.27, euthymia 0.41±0.26). CONCLUSIONS: Patients with BD-I and BD-II experienced a high level of functional impairment compared to healthy individuals. QoL was similar in both BD-I and BD-II, and was lowest in patients experiencing depressive and mixed episodes, and highest in hypomanic episodes and euthymia.