Coat proteins of several different plant viruses were transferred from entire leaves of infected hosts to nitrocellulose membranes in 2 min using a hydraulic laboratory press. Protein transfer was even across the leaf as evidenced by India ink staining of blots. Coat proteins of four different viruses were detected using virus specific IgG. The presence of viral coat proteins was observed as small intense spots whose distribution was irregular and coincided most frequently with the presence of chlorosis on the leaves. Detection was sensitive, and accurately reflected the distribution of virus symptoms across leaves.