We propose a new five-site pair potential for formic acid to beemployed in liquid state simulations. Thepair potential excellently fits to the MP2/6-31G(d) ab initiodimer potential surface, correctly captures thecharacteristics of the most important regions of the potential, andlocates all seven minima found in ab initiocalculations. Both thermodynamical quantities and total radialdistribution functions for liquid formic acidwere computed employing Monte Carlo simulation techniques. Wefound excellent agreement betweenexperiment and theory with respect to thermodynamics and structure.The results of the total radial distributionfunctions exhibit significant improvement compared to the results ofthe OPLS parameter set.