A 7-year-old girl had had abdominal pain, nausea, vomiting, and fever since the age of 2 years. When she was 3 years old she passed the first renal stone. During the next three years preceding hospitalization she passed stones on the average of one every one or two weeks. These episodes were usually accompanied by high fever, abdominal pain, and nausea. The cause was ultimately found to be a primary hyperoxaluria. A review of the literature shows that about half of the reported cases of urolithiasis in children have been ascribed to causes unknown, with only 10 % definitely traced to metabolic disease. This case suggests that more detailed study might often lead to recognition of the underlying metabolic aberration and that diagnostic laboratory procedures not generally available may sometimes be necessary if the patient is to be spared the consequences of misdirected treatment.