Context: More than half of the bipolar disorder (BD) cases have an additional diagnosis; one of the most difficult to manage is obsessive-compulsive disorder (OCD). Although some authors recently investigated the co-occurrence of anxiety and BD, the topic remains insufficiently studied. The current study aimed to investigate differences in comorbid OCD between BD-I and BD-II. Evidence Acquisition: A systematic review and meta-analysis was conducted on the prevalence and predictors of comorbid BDI/ BD-II and OCD. Relevant papers published until June 30, 2015 were identified searching the electronic databases MEDLINE, Embase, PsycINFO and the Cochrane Library. Results: Fourteen articles met the inclusion criteria. The pooled prevalence of BD-I in OCD was 3. 9% (95% confidence interval (CI), 2. 4 to 6. 4, I2 = 83%, Q = 56) while that of BD-II in OCD was 13. 5% (95% CI, 9. 3 to 19. 3, I2 = 89%, Q = 91). The pooled prevalence of OCD in BD-I was 21. 7 (95% CI, 4. 8 to 60. 3, I2 = 84%, Q = 95). With regard to OCD-BD predictors, mean age and rate of males did not predict the prevalence of BD-I ( = 0. 0731, 95% CI,-0. 1097 to 0. 256, z = 0. 78; = 0. 035, 95% CI,-0. 2356 to 0. 1656, z = 0. 34) and BD-II ( = 0. 0577, 95% CI,-0. 1942 to 0. 0788, z = 0. 83; =-0. 0317, 95% CI,-0. 1483 to 0. 085, z = 0. 53) in OCD. The mean age explained some of the observed heterogeneity (R2 = 0. 13; R2 = 0. 08). Conclusions: This first systematic review and meta-analysis of the prevalence and predictors of comorbid BD-I/BD-II and OCD suggests that BD-OCD comorbidity is a common condition in psychiatry. However, the available evidence does not allow to assess whether BD-I or BD-II are more common in patients with OCD.