The case of a seven and a half-year-old girl with hyperglycinuria, oxalate nephrolithiasis, and a normal plasma amino acid pattern is presented. Hyperglycinuria amounted to 400 mg of glycine in 24 h urine and the stone was composed of calcium oxalate dihydrate. The metabolic relationship between glycine and oxalate is discussed. It is possible that the association of nephrolithiasis and hyperglycinuria was coincidental, although the case of familial hyperglycinuria with nephrolithiasis reported by De Vries and collaborators and our case suggest the possibility of a relationship between the aforesaid compounds in vivo.