A structural investigation of liquid N methylacetamide was performed at 308 K using x-ray scattering. To extract the molecular form factor F-1(q), the geometry of the conformer which has been found in the crystal is considered. The intermolecular structure function D-M(q) is interpreted in terms of H-bonding interactions. The crystal N.O distance is taken into accounted and the number of H bond(s) is assumed to be, respectively, equal to one and two. The liquid structure can be described by a linear dimer or chainlike trimer similar to the ones existing in the crystal. The structure factors S-M(q) extracted from these clusters fairly agree with the experimental one beyond q=2.5 A(-1). (C) 2004 American Institute of Physics.