Aims: The clinical relevance of urethral pressure variations (UPV) in the pathophysiology of over active bladder syndrome (OAB) has remained controversial to date. Some studies report an association with OAB and/or detrusor over activity (DO). Recently the International Consultation on Incontinence-Research Society recommended new clinical research to be performed on this subject. We provide a systematic review of the literature to specify this recommendation. Methods: Literature search was performed in PubMed, Embase, Web of Science, Cochrane, Central, Cinahl, Academic Science Premier, Science Direct, and Wiley Online using a sensitive search string combination. All authors independently reviewed and scored full text papers and consensus about methodological quality was obtained according to Oxford Level of Evidence (LoE). Results: Four hundred eighty seven abstracts were screened, 25 papers met all predefined inclusion selection criteria. Incidence figures of UPV varied between 2% and 95%. Studies are of poor methodological quality with Oxford LoE scores of 3B and 4. Measurement methods and techniques show a large variety. The above mentioned association of DO/OAB with UPV is however frequently reported. Conclusion: There exists a phenomenon of UPV, apart from DO, which may be a separate entity within OAB syndrome. Large variation in measurement techniques and patient populations hinders fundamental research as well as clinical progress. Clinical relevance of UPV and consequences for treatment therefore are yet to be established. Future prospective research with well-defined patient population and standardised urodynamic measurement techniques is needed. Results of standardized and objective evaluations should be compared to clinical signs and symptoms by validated questionnaires. (C) 2015 Wiley Periodicals, Inc.