Molecular imprinted polymer (MIP) with methacrylate acid (MAA) as monomer and ethylene glycol dimethacrylate (EGDMA) as cross-linker in different molar ratios has been prepared. The free volume size and distribution have been derived from the measured positron lifetime spectra in MIP. The free volume size distribution observed clearly indicates the influence of the amount of cross-linker in the sample. Present results suggest that the optimum monomer cross-linker ratio is 1:5 for this MIP. Fourier transform infrared (FTIR) results confirm completer extraction of the 4-chlorophenol template molecules (4-CP) from the MIP with the absence of stretching frequencies at 648 and 825 cm(-1) for the C-Cl group. The free volume distribution analysis indicates that the percentage of accessible cavities to 4-CP molecules in this MIP is only 85% and less than those values reported in earlier studies.