Connecting arrangement between a syringe and an electromechanical pump for drug infusion, - wherein the syringe comprises a hollow cylindrical syringe body having a first, tapered open end for discharging the drug and a second open end, said syringe body being surrounded by connecting means arranged to firmly connect the syringe to the pump in a removable manner, an axially sliding plunger being housed in the syringe body for causing suction and injection of the drug through the first end, - wherein the pump comprises a pump body housing electromechanical members comprising a sliding rod arranged to cause sliding of the plunger within the body of the syringe connected to the pump, said pump body being provided with connecting means arranged to receive in an engaging configuration the syringe body, wherein: - the connecting means provided on the pump body comprise a cylindrical collar extending axially around the sliding rod and being internally provided with engaging elements, said collar defining a sealing end; - the connecting means surrounding the syringe body comprise engaging elements arranged to cooperate with the engaging means provided in the collar for firmly connecting the syringe to the pump in a removable manner, and an annular flange extending radially around the syringe body, said flange being adapted to cooperate with the sealing end defined in the collar in order to establish a tight sealing between the syringe body and the collar, whereby, when the syringe is attached to the pump, any moisture that may be present in the surrounding environment outside the pump and the syringe attached thereto does not penetrate into the pump body, characterized in that the collar is provided with at least one radial channel communicating the inside of the collar with the outside and in that said channel houses a porous element made of a material suitable for allowing passage of air and preventing passage of moisture. - wherein the syringe comprises a hollow cylindrical syringe body having a first, tapered open end for discharging the drug and a second open end, said syringe body being surrounded by connecting means arranged to firmly connect the syringe to the pump in a removable manner, an axially sliding plunger being housed in the syringe body for causing suction and injection of the drug through the first end, - wherein the pump comprises a pump body housing electromechanical members comprising a sliding rod arranged to cause sliding of the plunger within the body of the syringe connected to the pump, said pump body being provided with connecting means arranged to receive in an engaging configuration the syringe body, - the connecting means provided on the pump body comprise a cylindrical collar extending axially around the sliding rod and being internally provided with engaging elements, said collar defining a sealing end; - the connecting means surrounding the syringe body comprise engaging elements arranged to cooperate with the engaging means provided in the collar for firmly connecting the syringe to the pump in a removable manner, and an annular flange extending radially around the syringe body, said flange being adapted to cooperate with the sealing end defined in the collar in order to establish a tight sealing between the syringe body and the collar, whereby, when the syringe is attached to the pump, any moisture that may be present in the surrounding environment outside the pump and the syringe attached thereto does not penetrate into the pump body, characterized in that the collar is provided with at least one radial channel communicating the inside of the collar with the outside and in that said channel houses a porous element made of a material suitable for allowing passage of air and preventing passage of moisture.