The present invention relates to a method of producing formic acid in a catalysed chemical reaction from hydrogen gas and carbon dioxide gas, said reaction being conducted in an acidic medium comprising a polar solvent over a wide range of temperatures at total gas pressure of hydrogen and carbon dioxide up to 250 bar without the addition of base, carbonate, hydrogen carbonate or formate. The method of the present invention is advantageous since the reaction may be conducted in a polar solvent such as water or DMSO.