In 2006 the first version of a new ion source – desorption nanoelectrospray was developed in our laboratory. In this ion source, a spray capillary with internal diameter about 2 µm is used. From this point of view, the source represents miniaturization of desorption electrospray (2004) that uses capillaries with diameters in tens of micrometers. Nevertheless, the differences between the ion sources are more fundamental. In our lecture, technical development of desorption nanoelectrospray will be described, its comparison with desorption electrospray will be discussed and its selected applications will be shown, e.g. drug analysis in a blood drop or detection of wine adulteration.