Hello! I would like to know if it exists a simple way (R function, free software) to transform a CHP file ( Affymetrix MAS 5.0 output) into a .txt file or better into a .xls file. Thanks a lot for your response! Nicolas Nicolas Antille Statistician Nestl? Research Center PO Box 44, CH-1000 Lausanne 26 Phone: + 41 21 785 9433 <mailto:nicolas.antille@rdls.nestle.com>