Our aim was to develop an APpendictis-PEdiatric score (APPE score) in quantifying risk of acute appendicitis based on combination of clinical and laboratory markers. 1025 patients were classified in: acute appendicitis (AA) and non-appendicitis. Demographic/clinical features, and laboratory were collected. They were compared for quantitative-variables and categorical-variables. Significant predictors (P=<0,05) were included in logistic regression model. Based on regression-coefficients, a diagnostic score was tested by calculating the area under the ROC curve. Two cut-offs were established to define classes of risk of AA. 9 variables were identified as potentially predictors for AA. Those underwent logistic regression and a score was assigned, for maximum 21-points. The score showed an area under the curve: 0.831 and a linear proportion with the state of appendicular inflammation (R20.85). Patients with a score ≤8 were at low risk of AA (sensitivity 94%); those with a score ≥15 were at high risk for AA (specificity 93%). Those between 8 and 15 were defined at intermediate risk class. APPE-score guides clinicians in classifying patients with suspected-AA according to clinical and laboratory findings in order to improve their management.