A method and a set for transferring fluid between a first container a second container. The first container is connected to an end of a first transfer body, a first sealing member preventing the fluid communication between these two elements. The second container is closed by a second sealing member. The second container is assembled with a fastening member provided at an end of a second transfer body which is in an inactivated position of the transfer set wherein at least a part of this body is partially inserted within the other end of the first transfer body. Each transfer body has one central passage coaxial to accommodate at least one end of a mobile piercing member. The part of the second transfer body moves along an axis from the inactivated position to an activated position of the transfer set wherein the fluid communication between these two containers is established.