Background: Chronic and recurrent abdominal pain is a common symptom in children with prevalence ranging between 10% and 20%.  Community and school based studies reported that recurrent abdominal pain occurred in 7% to 25% of school-aged children and was severe enough to affect activities in 21 % of them. Chronic abdominal pain includes organic and nonorganic causes. Among organic causes is Giardia Lamblia which is the most important protozoan causing recurrent abdominal pain. Objective: Detection ofthe frequency of giardiasis in school children in Dakahlia Governorate with chronic recurrent abdominal pain using routine stools analysis and stools ELISA test for giardia antigen . Patients and methods: The present study was carried out on 200 school children ( primary, preparatory and secondary schools), aged 7-18 years, from Dakahlia Governorate during  the period from February 2016 to October 2016. School children chosen complained from chronic abdominal pain and one or more of the cumulative symptoms that support giardiasis like diarrhea, inefficient defecation ,vomiting, ,weight loss and generalized fatigue. Each child enrolled in the study was submitted thorough clinical examination, blood sample for complete blood count , and stool sample for microscopic stool analysis, and ELISA test for detection of giardia antigen. Anthropometric measurements (Height, weight and determination of nutritional status) were detected. Results : Routine stool analysis showed giardia cysts  in 50%of the examined  stool samples . ELISA detected the giardia antigen in 90% of the examined stool samples.  Regarding validity of stool analysis in relation to Giardia antigen by ELISA ,the sensitivity and specificity was  55.5% and 100% respectively  . The stool analysis agreed with ELISA antigen detection for giardiasis by 60%. Conclusion: Giardia Lamblia infection is a causative factor of the recurrent abdominal pain in children. Also, ELISA test for detection of Giardia Lamblia antigen in stool is more sensitive than ordinary stool microscopical examination for diagnosis of giardiasis.