Omphalitis contributes significantly to morbidity and mortality in neonatal calves. Diagnosis of omphalitis is based on the local signs of inflammation—pain, swelling, local heat and purulent discharge. An abattoir trial identified an optimal, sign-based, scoring system for diagnosis of omphalitis. A sample of 187 calves aged between 7 and 15 days old were clinically examined for signs of umbilical inflammation and compared with postmortem examination of navels. On postmortem findings, 64 calves (34.2 per cent) had omphalitis. In the examined omphalitis cases, the most commonly affected umbilical structure was the urachus (78.1 per cent). Multivariable logistic regression revealed that thickening of the umbilical stump over 1.3 cm (P<0.001), discharge (P<0.001), raised local temperature (P=0.003) and the presence of umbilical hernia (P=0.024) were correlated and positive predictors of omphalitis. Discharge from the umbilical stump was associated with intra-abdominal inflammation (P=0.004). Assigning weights based on the multivariable logistic regression coefficients, a clinical scoring algorithm was developed. The cumulative score ranged from 0 to 9. Using this scoring system, calves were categorised as positive if their total score was ≥2. This scoring method had a sensitivity of 85.9 per cent, specificity of 74.8 per cent and correctly classified 78.6 per cent of all calves.