We aimed to describe and evaluate the National Early Warning Score (NEWS) in the 24 hours preceding an in-hospital cardiac arrest among general somatic ward patients. The 24 hours preceding the in-hospital cardiac arrest were divided into four timespans and analysed by a medical record review of 127:254 matched case-control patients. The median NEWS ranged from 3 (2–6) to 6 (3–9) points for cases vs 1 (0–3) to 1 (0–3) point for controls. The proportion of cases ranged from 23–45% at high risk vs 3–6% for controls. The NEWS high-risk category was associated with an increase of 3.17 (95% confidence interval (CI) 1.66–6.04) to 4.43 (95% CI 2.56–7.67) in odds of in-hospital cardiac arrest compared to the low-risk category. NEWS, with its intuitive and for healthcare staff easy to interpret risk classification, is suitable for discriminating deteriorating patients with major deviating vital signs scoring high risk on NEWS.