Objective: Existing studies relating tothe prevalence of alcohol-related neurocognitive disorders (ARNDs; e.g., Korsakoff’s Syndrome, alcohol-related dementia) are now outdated and few have been undertaken in the United Kingdom. The aim of this study was to estimate theprevalenceofARNDs in SouthWales, U.K., and determine the specific diagnostic terms and criteria used in clinical practice. Method: Anaturalistic, survey-based prevalence study was undertaken wherein data were collected retrospectively for all individuals with ARNDs attending services during all of 2015 and 2016. Adiverse sample of health and social care services (N =60) in South Wales took part inthe study. Results: Atotal of 490 individuals with ARNDs were identified by participating services, equating to an age-specific rate of 34 individuals per 100,000 inhabitants. Variability wasobservedacross age ranges and genders, with most identified in the 45–64 year age range and amale:female ratio of 2.6:1.Twenty-three individuals younger thanage 35 were identified,demonstrating an increase in younger cases compared with previous studies. Variousdiagnostic termswere used, with “alcohol-related brain damage” being mostcommon.Only6.3%ofcases were diagnosed according to specific criteria and 44.3% were reported as having a“probable” ARND, meaningnoofficial diagnosis had been designated butinitial assessments indicated that they likelyhad an ARND. Conclu-sions: Findings provide anovel understanding of ARND prevalence in apreviously understudied area, although the prevalence estimate is conservative and should be interpreted cautiously for reasons discussed. Findings also highlight an inconsistency between diagnoses presented in nosological systems (e.g., International Classification of Diseases–10th Revision) and those used in practice and therefore aneed to evaluate novel diagnostic conceptualizations of alcohol-related neurocognitive impairment.