Introduction: Hemsley and Garety described the "jumping to conclusions bias" in which patients with delusions may reach unreasonable results with insufficient information. In this study patients with bipolar disorder and healthy volunteers were compared in terms of jumping to conclusions bias using the beads in the jar task. Methods: 37 patients with DSM-5 diagnosis of bipolar disorder and 30 healthy controls were tested with the Beads Task (BT), Tower of London Test (ToL) and Barrat Impulsiveness Scale (BIS). Results: In the BT, the mean score of DtD (draws to decision) and JTC (jumping to conclusions) scores were not statistically different between the two groups. In the ToL test, the duration of the total execution and the total time were significantly longer in the bipolar group than the control group. BIS scores were significantly higher in the bipolar group. YMRS (Young Mania Rating Scale) scores were not correlated with BT. Conclusions: This study is the first clinical study to assess the jumping to conclusions bias in patients with bipolar disorder. No JTC bias was detected in bipolar disorder. Further studies may assess JTC in larger samples to determine the effects of clinical state changes, psychotic symptoms, medication and impulsivity.