Since the last reviews in this series on plant proteins by Danielson (1) and on leaf proteins by Pirie (2), the application of new methods for the isolation and identifi cation of proteins in plant tissues has added consider able new information about the protein components of plants. Fractionation of plant protein preparations through ion-exchange chromatography on cellulose derivatives and by gel-electrophoresis has revealed many previ ously unrecognized protein components in extracts of various plant tissues. Many plant protein preparations previously considered as a single protein have been shown to contain several different components. This is the result of a revolution over the past 15 years in the techniques available for the analysis and isolation of proteins. An excellent three-volume description of these new techniques has been edited by Alexander & Block (3). The earlier review by Danielson on proteins (1), and articles on methods for separation and making and handling extracts [Pirie (4, 5)], contain much information of value to the scientist interested in the isolation and study of plant proteins. The earlier reviews in this series have dealt with the classifi cation of plant proteins and the homogeneity of seed proteins (1); and with the isolation of leaf proteins (2). This review will be concerned with the more recent papers on plant proteins from both seeds and leaves as well as new methods that may be used for the isolation and identification of plant proteins. No attempt will be made to review work in the field of pro tein synthesis which was covered by a recent review in this series (6). A survey of publications on plant proteins shows that many laboratories limit their studies to proteins from a single or a few related plant species; con sequently, in this review we will discuss together those papers that deal with proteins from the same or related plant sources. The methods used by most workers in the isolation and identifi cation of the plant proteins will be mentioned when their papers are discussed and a short summary of the more recent methods for the identification of proteins is included.