Purpose We conducted a prospective multicentre study in 13 Welsh intensive care units to assess what proportion of intensive care admissions relate to alcohol, and how outcomes among these patients compare with non-alcohol related admissions. Materials and methods Data were prospectively collected for one month between June and July 2015. Every intensive care admission was screened for alcohol associations based on ICD-10 criteria, using a pre-designed pro-forma. Follow-up data were collected at 60 days using a pre-existing database (WardWatcher; Critical Care Audit Ltd, England). Outcomes included: lengths of mechanical ventilation, intensive care units and hospital stay; intensive care units and hospital mortality. Results Alcohol contributed directly to 10% of all ICU admissions and to 11% of unplanned admissions. These patients were younger (52 vs. 66, p = 0.0011), more likely to be male (68% vs. 52%, p = 0.014) and had more prolonged ventilation (p = 0.019) There was no significant difference between the groups with respect to length of stay or mortality. Conclusions Alcohol contributes to a significant proportion of ICU admissions in Wales, a Western European country with a relatively low number of ICU beds per capita. Strategies to address this impact should be explored.