This study was designed to investigate effectiveness of fragmentation during lithotripsy using 103 intrahepatic stones collected from 10 patients, who had previously undergone biliary surgery. The size of each stone was measured and sonography was performed for the evaluation of the sonographic type of the stones. In vitro lithotripsy was performed on individual stones using piezoelectric lithotriptor to evaluate the fragmentation rate and average number of shock waves for fragmentation. Chemical analysis of each stone was done to determine chemical composition including calcium, bilirubin, and cholesterol. The size of the stones was from 5mm to 20mm in diameter. Sonographic type I (echo of whole stone with posterior acoustic shadow) was 35 in number. The majority (78%) of stones in group 1 (5-9mm in diameter) showed sonographic type I characteristics, and 62% of stones in group 3 (larger than 15mm in diameter) showed sonographic type II characteristics. There was a positive c rrelation between the size and sonographic type of stones. Fragmentation rates of stones were 100% in group 1, 71.9% in group 2 (10-15mm in diameter), 43.8% in group 3, respectively. Fragmentation rates of stones with sonographic type I and II were 91.2%, 65.7%, respectively. The average number of shock waves for partial and complete fragmentation was 2753$pm$4937 and 6219$pm$10133, respectively. There was a positive correlation between the number of shock waves for fragmentation and diameter of stones (r=0.618, p<0.05). There was no correlation between the number of shock waves for fragmentation and chemical composition of stones. In conclusion, the most important variable determining the degree of fragmentation of intrahepatic stones using ESWL is not their chemical composition but their size and sonographic characteristics.