A three diamensional (3D) bicontinuous skeleton macroporous monolith was firstly prepared by in situ atom transfer radical polymerization (ATRP) of ethylene glycol dimethacrylate (EDMA) at the room temperature. The structure of the monolith could be mediated by the different ratio of EDMA to initiator and the 3D bicontinuous skeleton structure was obtained at the ratio of 70:1. Compared with the traditional monoliths prepared by conventional free radical polymerization, the monolith made of ATRP could be trended to form the 3D bicontinuous skeleton macroporous structure, due to low concentration of free radical and the step-wise growth of polymer chains in ATRR The diameter of the monolith could be enlarged to 50 mm without obvious volume shrink and cracks in the body. The morphology and pore distribution of the monolith were characterized by SEM and mercury intrusion porosimetry. The monolith was modified by grafting polymerization of n-butyl methacrylate, and then the grafted monolith was used to separate some steroids and proteins by reversed-phase liquid chromatography. (C) 2010 Elsevier Ltd. All rights reserved.