Plant long non-coding RNA database (PLncDB) attempts to provide the following functions related to long non-coding RNAs (lncRNAs): (i) Genomic information for a large number of lncRNAs collected from various resources, (ii) an online genome browser for plant lncRNAs based on a platform similar to that of the UCSC Genome Browser, (iii) Integration of transcriptome datasets derived from various samples including different tissues, developmental stages, mutants and stress treatments, and (iv) A list of epigenetic modification datasets and small RNA datasets. Currently, our PLncDB provides a comprehensive genomic view of Arabidopsis lncRNAs for the plant research community. This database will be regularly updated with new plant genome when available so as to greatly facilitate future investigations on plant lncRNAs.