Abstract VESPA, an improved semiempirical method for the calculation of electrostatic potential-derived atomic charges has been tested. It is shown that this approach is even less dependent upon molecular orientation than high density CHELPG ab initio ESP-derived charges. The conformational dependence of VESPA charges has been investigated for rotation around the C-N bond in formamide and 11 different conformers of glycerolphosphorylcholine. The results obtained are also compared to the corresponding ab initio values. Finally, VESPA is used to calculate electrostatic potential-derived charges for bioorganic molecules. We discuss the abilities and the limitations of ESP charges in this area.