The properties of the liquid N-methylformamide (NMF) at normal conditions are studied by means of NVT and NPT molecular dynamics (MD) simulation techniques. The liquid has been modeled for the first time via MD as a mixture of two conformers (cis and trans) with mole fraction X-trans = 0.94. A new all atom interaction potential model has been constructed and its reliability in predicting certain properties of the system has been presented. The results obtained reveal the existence of some differences regarding the dynamic and structural properties of the two conformers in the fluid. (C) 2003 Elsevier B.V. All rights reserved.