The purpose of this study was to develop and validate a pressure ulcer risk assessment for acute hospitals. This tool was developed in a cohort of 342 patients with a mean age 63 years (SD 19.82) and validated in a second cohort of 165 patients with a mean age 68 years (SD 18.40). Risk factors for inclusion on The Northern Hospital Pressure Ulcer Prevention Plan (TNH-PUPP) were identified from the literature then examined and weighted using logistic regression. Risk factors included on the TNH-PUPP were requires assistance to move in bed (odds ratio [OR] 5.15; 95% confidence interval [CI]: 2.49-10.65), admission to intensive care during current admission (OR 2.98; 95% CI: 1.33-6.67), aged ≥ 65 years (OR 2.81; 95% CI: 1.24-6.36), reduced sensation (OR 2.29; 95% CI: 1.19-4.42), and cognitive impairment (OR 2.26; 95% CI: 1.09-4.67). The TNH-PUPP was validated in a prospective sample. The new tool had high diagnostic validity (area under the receiver operating curve=0.86), consistent in the validation sample (area under the receiver operating curve=0.90). The TNH-PUPP has a moderate positive predictive value (development=0.50; validation=0.13), and a high negative predictive value (development=0.94; validation=0.99) enabling low-risk patients to be screened out, as noncandidates for pressure ulcer prevention interventions. An accurate pressure ulcer risk assessment has been developed and validated, which identifies a high-risk group to whom limited pressure ulcer prevention resources should be directed. The TNH-PUPP facilitates effective resource allocation and is likely to reduce unnecessary patient harm and costs from pressure ulcers in acute hospitals.