We propose high osmotic pressure chromatography (HOPC) to separate a large amount of polydisperse polymeric materials into fractions with different molecular weights. A concentrated polymer solution is introduced into a chromatographic column packed with porous materials that provide the polymer with sufficient geometrical confinement. The injection is continued until the polymer is detected at the column outlet. Then, the injection is switched to the pure solvent, and the eluent is collected into different test tubes. The separation principle is based on the segregation that takes place between pore channels and the surrounding solution, as a high osmotic pressure of the concentrated polymer solution drives low molecular weight components preferentially into the pore channels. As the polymer solution is transferred along the column, enrichment of the highest molecular weight components in the mobile phase is repeated at the solution front until it reaches the outlet. It is followed by the next highest molecular weight components. The molecular weight of fractions collected at the column outlet monotonically decreases as the number of fractions increases, but it is accompanied by a broadening of the distribution. The molecular weight distribution is narrow, especially for initial fractions. We demonstrate HOPC using silica gels as the porous materials for broad-distribution polystyrene, polystyrene standards, and other amorphous polymers.