Hi BioC, I have found readGEOAnn() which provides me below information. HOW can I built Expression set for GEO files? Has anyone done such thing? Any help will help..! >gpl96 <- readGEOAnn(GEOAccNum = "GPL96") >attributes(gpl96) $dim [1] 22283 25 $dimnames $dimnames[[1]] NULL $dimnames[[2]] [1] "ID" "GB_ACC" [3] "Sequence Source" "UNIGENE" [5] "LOCUSLINK" "Gene Title" [7] "Gene Symbol" "Species Scientific Name" [9] "Annotation Date" "Sequence Type" [11] "Transcript ID" "Target Description" [13] "Representative Public ID" "Archival UniGene Cluster" [15] "Chromosomal Location" "Ensembl" [17] "SwissProt" "EC" [19] "OMIM" "RefSeq Protein ID" [21] "RefSeq Transcript ID" "Gene Ontology Biological Process" [23] "Gene Ontology Cellular Component" "Gene Ontology Molecular Function" [25] "SPOT_ID" Thank you in advance, Saurin Jani -- |------------------------------------------------ | Saurin Jani,MS | Statistical and Research Analyst | | Department of Cell Biology and Anatomy | Medical University of South Carolina (MUSC) | 173 Ashley Ave | Charleston,SC - 29407 (US) | | Email: jani@musc.edu | Phone: (843)792-5483 |------------------------------------------------