Peroxisomes play an essential role in human cellular metabolism. Peroxisomal disorders, a group of genetic diseases caused by peroxisomal dysfunction, can be classified into three groups: (1) disorders of peroxisome biogenesis with a generalized loss of peroxisomal functions (Zellweger syndrome, neonatal adrenoleukodystrophy, infantile Refsum disease, hyperpipecolic acidaemia); (2) disorders with a loss of multiple peroxisomal functions (rhizomelic chondrodysplasia punctata and Zellweger-like syndrome; (3) disorders with loss of a single peroxisomal function (X-linked adrenoleukodystrophy, peroxisomal thiolase deficiency, bifunctional protein deficiency, acyl-CoA oxidase deficiency, classic Refsum disease, hyperoxaluria type I and acatalasaemia). Prenatal diagnosis is indicated in all these genetic disorders with the exception of classic Refsum disease, most types of hyperoxaluria type I and acatalasaemia. A variety of techniques is available now for the prenatal diagnosis of peroxisomal disorders in the first or second trimester of gestation. Prenatal diagnosis was performed by us in 70 pregnancies at risk for a disorder of peroxisome biogenesis, three for rhizomelic chondrodysplasia punctata, four for X-linked adrenoleukodystrophy and two for a defect in peroxisomal beta-oxidation. Fourteen affected fetuses were identified; no false negative cases were obtained.