INTRODUCTION The Pediatric Crohn Disease Activity Index (P CDAI is one of a non invasive method s for monitoring the effect of Crohn's disease treatment in the pediatric population. AIM The aim of this paper is to compare the value of PCDAI, the phenotype and severity of the disease between male and female patients, to determine whether there are differences in the clinical picture between patients with earlier and later onset of the disease, and to examine how well the value of PCDAI reflects the inflammatory activity of the intestinal mucosa. METHODS This retrospective cohort study included patients with Crohn's disease who were treated at the Zagreb Clinical Hospital Center in the Department of Gastroenterology, Hepatology and Nutrition in the period from January 1, 2011 to January 1, 2023. BIS (Hospital Information System) was reviewed as source of dana. RESULTS 44 patients were analyzed, of which 30 ( were male and 14 ( were female. At the time of diagnosis, the majority of patients presented with an inflammatory phenotype (37 patients 84.1% and a mild form of the disease (31 patients 70.5%). By comparing patients by gender, no statistically s ignificant difference was found according the age of onset of the first symptom, the frequency of early and later onset of the disease, nor the frequency of different CB phenotypes. In patients with early and also in those with a later onset of the disease the most common phenotype of CB was inflammatory, and no statistically significant difference was found in the PCDAI value between these two groups of subjects (p= According to the PCDAI value, no statistically significant difference in phenotype was found between patients with a mild and those with a more severe form of the disease (p= the most common form in both groups was inflammatory. CONCLUSION Gender and time of disease onset do not influence the phenotype and severity of Crohn's disease. The value of PCDAI does not correspond well with the inflammatory state of the intestinal mucosa and therefore is not a reliable tool for monitoring the outcome of CB treatment.