Objectives: To determine the biochemical composition and biochemical typesof childhood urolithiasis. Study Design: Cross sectional study. Place and Duration: PediatricSurgery Department, Liaquat University of Medical and Health Sciences, and University ofSindh, Jamshoro over one year. Subjects & Methods: 30 pediatric cases urinary bladderurolithiasis were selected. Children of age few of ten years were selected. Any contaminationform bladder stone was removed by washing them in distilled deionized water. Stones weredried for an overnight in an oven at temperature of 100 0C. Dried stones were smashed intopieces. Biochemical analysis was performed by the FTIR spectroscopy (Nicolet Avatar 330FTIR spectrophotometer). Results were analyzed on the software SPSS 22.0 (95% confidenceinterval). Results: Mean age was 4.83 years (SD 2.81 years). Of 30 children, 80% (n=24) weremale and 20% (n=6) were female children. Male to female ratio of 4:1 was noted. 16.6% (n=5)were pure stone and 83.3% (n=25) were mixed stones. (P=0.0001). Biochemical analysisshowed the calcium oxalate monohydrate (COM)-ammonium hydrogen urate (AHU) was themost common urinary bladder stone. Conclusions: The pediatric urolithiasis shows the mostcommon type of urinary bladder stone was the calcium oxalate monohydrate–ammoniumhydrogen urate.