Medical Sciences. In the article “Molecular cytogenetic delineation of a novel critical genomic region in chromosome bands 11q22.3-q23.1 in lymphoproliferative disorders” by Stephan Stilgenbauer, Peter Liebisch, Michael R. James, Martin Schröder, Brigitte Schlegelberger, Konstanze Fischer, Martin Bentz, Peter Lichter, and Hartmut Döhner, which appeared in number 21, October 15, 1996, of Proc. Natl. Acad. Sci. USA (93, 11837–11841), the authors request that the following printer’s error be corrected. All band designations contain a “9” instead of a “q” as annotation of the distal band number. We apologize for this error.