A process for producing spherical porous organic microspheres, based on urea-formaldehyde (UF) polymer, has been developed. These microspheres exhibit exceptional mechanical strength and resiliency and have minimal tendency toward shrinking or swelling in aqueous, organic, or hydroorganic media. The geometric parameters of the microspheres are conveniently adjusted by process variables, which allow precise control of pore and particle dimensions. The surface of the UF microsphere contains organic functional groups suitable for chemical modification so that ligands of choice may be covalently attached for operation in the anion-exchange or hydrophobic interaction modes.