The first documented case of propionic acidemia in Israel is described. Diagnosis was based on three independent methods: analysis of urinary organic acids by gas chromatography/mass spectrometry, assay of propionyl CoA carboxylase activity and oxidation of 1-14C-propionate by cultured skin fibroblasts. The use of more than one method for confirmation of the diagnosis is considered to be of importance in providing an additional margin of safety in cases where genetic counseling and prenatal diagnosis in future pregnancies are indicated.