....... MicroPC ( µPC : A comprehensive resource for Predicting and Comparing plant MicroRNAs) is an online resource that provides comprehensive information of plant miRNAs from two sources including previously reported miRNAs from miRBase and predicted miRNAs and their targets from our large scale Expressed Sequence Tags (ESTs) analysis. µPC aims to give a comprehensive view of conservation, evolution and function of plant miRNAs via incorporated utilities (1) Comparative enables users to explore the conservation of known and predicted miRNAs among plant species in integrative views, (2) Search provides various ways for users to access predicted miRNA candidates and potential miRNA targets in detail, and (3) Prediction helps to predict whether an input nucleotide sequence is a potential miRNA candidate and to scan for EST sequences of a plant species potentially targeted by an input mature miRNA sequence.