Abstract Summary: IE-Kb (Intron Exon-Knowledge base) illustrates the intron–exon dynamics in eukaryotic genes. We have developed three different knowledge sets, namely ‘Non-redundant ExInt’, ‘Non-redundant Pfam-ExInt complement’ and ‘Non-redundant GenBank eukaryotic subdivisional sets’ to understand this phenomenon. Statistical analysis is performed on each knowledge set and the results are made available online. The entries in knowledge sets are ranked based on their intron length, exon length and protein length with relational hyper-links to the corresponding intron phase, intron position, intron sequence, gene definition and parent GenBank entry. Availability: http://intron.bic.nus.edu.sg/iekb/iekb.html Contact: [email protected] * To whom correspondence should be addressed.