The Alvarado scoring (AS) system was created with the intention to reduce the number of negative appendec-tomies. It is used in both the adult and pediatric populations, but the number of negative appendectomies is rarely lower than 10%. In order to test the reliability of the system, an analysis was done on the correlation of the Alvarado score and the histological diagnoses of children who underwent appendectomy for suspected acute appendicitis. This retrospective study was conducted at the Department of Pediatric Surgery of the Uni-versity Hospital Center Zagreb in the period between January 2014 and December 2016, and included 330 children with the clinical diagnosis of acute appendicitis. The children were included regardless of the method of appendectomy. As 39 of them were excluded due to incomplete medical records, only 291 children were analyzed. Each appendix was subjected to postoperative histological examination, after which the final diagno-sis was made. Abdominal ultrasound was performed in 160 children to detect whether there were signs of ap-pendicitis. 291 appendices were histologically examined, of which 35 (12%) were without inflammatory signs, 44 (15.1%) were in the catarrhal, 153 (52.6 %) in the phlegmonous, and 58 (19.9 %) in the gangrenous stage of inflammation; one boy (0.3 %) had a perforated appendix. The average value of the Alvarado score in children with histologically innocent or catarrhal appendix was 6, in those with phlegmonous 7, and in those with gangrenous 8. The boy with the perforated appendix had a score 6. Sensitivity, specificity, and positive predictive value (PPV) with the cut-point of 7, as well as negative predictive value (NVP) with the cut-point of 5, were analyzed. In the tested group, AS sensitivity and specificity were 68.9% and 52.9%, respec-tively. Positive predictive value was 91.7% and negative predictive value was 99%. AS was statistically signifi-cantly higher in children with phlegmonous appendicitis than in those with innocent appendix (p = 0.003) or with a catarrhal stage of inflammation (p = 0.007), as well as in children with gangrenous appendicitis com-pared to those with innocent and catarrhal appendicitis (p < 0.001). There was no statistically significant dif-ference between AS in children with phlegmonous and gangrenous appendicitis (p = 0.054), and neither be-tween AS in those with catarrhal and innocent appendix (p = 0.998). The abdominal ultrasound examination was performed preoperatively in 160 (54.9%) of all operated children. Only 82 (51.2%) of all ultrasound find-ings were consistent with the final histological diagnosis. Among those incongruous findings, there were 64 (40%) false negative and 14 (8.8%) false positive ones. Ultrasound showed the presence of appendicitis with a PPV of 84.1%, but for exclusion of the diagnosis NPV was 11.1 %. AS is not a reliable clinical indicator of the inflammatory signs of appendicitis in children, but still has a high predictive value for negative appendecto-mies.