Abstract Background Despite various pharmacological and psychological treatment interventions, bipolar disorders rank among the leading causes of global disease burden. Group psychoeducation has been demonstrated an effective add-on to pharmacotherapy, but it may be difficult to implement in practice depending on the clinical setting and available human resources. Methods Multicenter, rater-blind, randomized controlled trial to investigate the efficacy of a new intervention program consisting of an initial 6-week psychoeducation protocol plus a subsequent structured daily computer-based self-charting program (ChronoRecord) over 54 weeks in remitted patients with bipolar disorders. The control condition included non-structured group sessions followed by daily computer-based self-reports (unstructured like a diary). Both groups received treatment-as-usual. Results Over 2 years, 41 mood episodes occurred in the experimental group (n = 39) compared to 27 in the control group (n = 34), without reaching statistical significance. Time to recurrence did not significantly differ between the experimental and control group (25% relapsed after 112 and 273 days, respectively). There were no significant group-by-time interactions in mood symptoms, quality of life, self-efficacy expectations or perceived involvement in care. Conclusions Six weekly psychoeducational group sessions followed by daily self-monitoring via ChronoRecord for 54 weeks may not be superior to non-structured group meetings followed by unstructured self-reporting. Other psychotherapeutic interventions may be needed to optimize the treatment of patients with bipolar disorders, especially for those at later disease stages. Trial registration Retrospectively registered at German Clinical Trials Register on May 24, 2019; DRKS00017319