Outstanding Paper Award Subcommittee of Journal of Chemical Engineering of Japan has assessed the 171 papers published in 2006, corresponding to volume 39 and selected the candidates of the award. As a result, the editorial board finally selected the five papers for JCEJ Paper Awards of 2006; those are the papers on "Preparation and Gas Permeation Properties of Composite Carbon Molecular Sieve Membranes Derived from Polyimides with Thermally Decomposable Sulfonic Acid Salt and/or Hexafluoroisopropylidene Group," "Application of Association Model for Solubilities of Alkali Metal Chloride in Water Vapor at High Temperatures and Pressures," "Epitope Screening by Use of a Random Peptide-Displayed Phage Library and Polyclonal Antibody-Coupled Liposomes," "Crystallization of Ergosterol from Hexane Solution by a Continuous Column Crystallizer Equipped with a Water Feeding System," and "Numerical Investigation of Local Oxygen Injection Effect on Argon Induction Plasmas Using a Chemically Non-Equilibrium Model".