Abstract: A process for selectively removing nitrogenated and/or sulfurated contaminants from streams prevalently containing hydrocarbons with from 3 to 8 crbon atoms characterized in that it comprises an adsorption step wherein said contaminants are adsorbed by an adsorbent essentially consisting of silica gel at a temperature of between 0 and 150.degree. C. and at a pressure of between 1 and 20 atm and a regeneration step to remove the adsorbed substances by thermal treatment in a stream of insert gas carried out at a temperature of between 100 and 200.degree. C.