New benzenesulfonyl asymmetric ureas are herein disclosed, corresponding to the general formulas (I) -(IV) and pharmaceutically acceptable salts thereof, whose structure and substituents are detailed in the specification. Procedures for the synthesis of these compounds are disclosed. The compounds are active on the ghrelin receptors, in particular they have inverse agonist activity; they are useful in preventing and/or treating diseases pathophysiologically mediated by the ghrelin receptor, like e.g. obesity, diabetes and substance abuse. Also disclosed are pharmaceutical compositions comprising a compound as herein defined and a pharmaceutically acceptable carrier or vehicle.