In the articles “Serum Levels of Oncofetal Markers CA 125, CA 19-9 and α-Fetoprotein in Childern with Hereditary Tyrosinemia Type I” by S. Pitkänen et al. (Pediatr Res 35:205-208, 1994) and“Tumor Markers CA 125 and CA 19-9 in Cord Blood and During Infancy: Developmental Changes and Use in Pediatric Germ Cell Tumors” by P. Lahdenne et al. (Pediatr Res 38:797-801, 1995) the units for serum CA 125 and 19-9 given in “U/L” should be “U/ml.” The authors apologize for this error and regret any confusion they might have caused the readers of Pediatric Research.