Abstract Background & aim: Urinary stone is one of the important causes of morbidity among children. The aim of this study was to determine the effective factors of Pediatric Urolithiasis in Children under the age of 14. Methods: In this case-control study, among children under 14 years of age referring to the Shahid Beheshti Clinic of Yasuj with the diagnosis of urolithiasis confirmed twice by ultrasound, 48 children were selected as eligible cases for the questionnaire containing demographic information, the location, and size of the stone were completed. Of 48 healthy children younger than 14 years referring to the clinic for evaluation of growth and health were selected as the control group. Affecting parameters of serum and urinary stone formation in both groups were controlled. The collected data were analyzed by using statistical mean tests, chi-square and t-tests. Results: In 70.8% of the group case, children had a positive family history of urolithiasis. Hypercalciuria, Hyperoxaluria, hyperuricosuria, and Hypocitraturia were found 35.4%, 17.8%, 13.6%, and 13.6% in group case respectively. Mean urinary calcium level of the case group was 0.47 and in controls, 0. 24. The mean urinary uric acid level of the case group was 0.91 and for the control was 0.54 (05/0> p). In 58.3% of the cases, a single kidney stone was seen and in 95.8% of the cases, the size of 4 mm or less were observed. The most common symptoms of urolithiasis (58.1%) at admission were restlessness and irritation during urination. Conclusion: According to the results of study, Hypercalciuria, Hyperoxaluria, Hyperuricosuria and positive family history are the major cases of urinary stones in children which are often individual with the size of 4 mm. Key words: urolithiasis, children, hypercalciuria