A butterfly needle (100) for venipuncture comprises a body (1) with two outwardly protruding flexible wings (2) foldable by manual gripping by the user from a diverging position to a converging position, and a needle (9) mounted axially in the fore end (32) of a needle-carrier (3) which has a tail (8) protruding rearward from said body (1) to couple with the connection of a flexible tube designed to be connected to a syringe or bottle. A substantially cylindrical needle cover (5), hollow on the inside, is mounted to slide axially inside the body (1) to pass from a retracted position of use in which it leaves the needle (9) free and protruding forward from the body (1) to a forward position of safety in which it protrudes forward from the body (1) to cover the needle (9).