Data describing bipolar disorder in older adults people are scarce, particularly with regard to functional status. This observational, comparative study assessed psychosocial functioning in 33 euthymic older adults with bipolar disorder compared with 30 healthy controls. In addition, we evaluated the association between clinical variables and poor functioning in the patient group. The mean age of the group was 68.70 years. Patients with bipolar disorder experienced poorer psychosocial functioning (19.15 ± 11.36) than healthy controls (5.17 ± 3.72; p = 0.0001), as assessed using the Functioning Assessment Short Test. Significant differences between the groups were found for specific domains of functioning: autonomy, occupational functioning, cognitive functioning, financial issues, and interpersonal relationships (p = 0.0001, respectively). The largest variation was observed in overall functioning (Cohen’s d = 0.63). The number of previous hospitalizations was strongly associated with poor overall functioning (F = 7.217, p = 0.002). Older patients with bipolar disorder had a greater functional impairment than the healthy control group. Implementation of novel rehabilitation models is critical to help patients manage their illness.