AbstractGel permeation chromatography (g.p.c.) with organic solvents is of immense value in the characterisation of plastics and resins. Topics reviewed here are column packings and packing techniques, instrumental features, theories of the separating process and of instrumental dispersion, the use of g.p.c. to measure molecular size and hydrogen bonding, the applications of g.p.c. to low molecular weight polymers, applications to high molecular weight polymers, work on glass beads (as opposed to organic beads) and high resolution g.p.c.