Background: Cognitive impairment in end-stage kidney disease patients on dialysis is increasingly common. This study aimed to review the practice of screening and to evaluate the evidence on cognitive impairment prevalence in this population. Methods: This scoping review of studies summarises the evidence on cognitive impairment in dialysis populations. The search included the Medline, CINAHL, Embase, PsycINFO, PubMed, and Cochrane Library databases for English-language articles published between 2000 and 2015. A total of 46 articles were reviewed. Results: The studies were of prospective observational design, with the majority conducted in the haemodialysis population. The reported prevalence of cognitive impairment ranged from 6.6 to 51%. Three screening tools were consistently used. Conclusion: While cognitive impairment is recognised in the dialysis population, there is paucity of screening data. The design of prospective comparisons ideally includes established screening instruments, particularly the Montreal Cognitive Assessment, to determine the optimal results for this population. Translation of established screening tools to increase the inclusion of people from other cultural and language groups is required. Regular screening can enhance the timing to introduce home-based care support and advance care planning discussions.