Aim: The aim of this study was to evaluate the coexistence of obsessive-compulsive symptoms with bipolar disorder (during the manic phase, depressive phase and remission). Method: The subjects were 70 patients previously diagnosed with and treated for bipolar disorder. For the purposes of this study, three subgroups were created: patients in the manic phase, depressive phase and in remission. The Hamilton Depression Rating Scale, Young Mania Rating Scale and Yale-Brown Obsessive Compulsive Scale were diagnostic tools used for the evaluation of patients’ mental health. Results: The data indicate high likelihood of co-occurrence of obsessive-compulsive disorder (28.6%) and obsessive-compulsive syndromes (32.8%) with bipolar disorder. Obsessions and compulsions were observed irrespectively of the type of bipolar disorder (type 1 and 2) and phase of the illness (depression, mania, remission). The results in the three subgroups were similar. The severity of anankastic symptoms depended both on the severity of depression and mania. The subjects confirmed the presence of obsessive-compulsive symptoms in the interview, although they were usually undiagnosed and untreated. Conclusions: Obsessive-compulsive disorder symptoms often coexist with bipolar disorder, both in its two phases and in remission. The severity of obsessive-compulsive symptoms in the course of bipolar condition varies, ranging from mild to extremely severe forms. The obsessive-compulsive disorder presentation in the course of bipolar disorder increases with the severity of depressive and manic symptoms. Obsessive-compulsive disorder can be primary to bipolar disorder. Obsessive-compulsive disorder coexisting with bipolar disorder is not diagnosed or treated properly.