Monolithic supports for size exclusion chromatography (SEC) have been synthesized by ring-opening metathesis polymerization and were characterized by mens of inverse SEC. Variation sin the monoliths' composition were carried out to generate a microstructure with continuous porosity. Good quantification of the molecular weights of nine narrow polystyrene standards used as unknowns was observed. Analysis times were less than five minutes, offering an attractive access to high-throughput polymer analysis.