The furan (C4H4O) molecule has been studied using electron momentum spectroscopy at an impact energy of 800 eV. Binding energy spectra ranging up to 31 eV have been measured at target electron momenta from about 0.1 to 3.6 au. Electron momentum profiles of individual orbitals are obtained by deconvolution from a series of the spectra measured at selected electron momenta. The experimental momentum profiles are compared with theoretical ones calculated using the 6-31++G** basis set. Band assignments and the electron correlation effects are investigated through the orbital-specific momentum profiles. The results are compared with Green's function calculations by G. Bieri, L. Åsbrink, and W. von Niessen (J. Electron Spectrosc. Relat. Phenom. 27 (1982) 129) in terms of the ionization energies and their corresponding pole strengths.