Method of automatically deboning poultry breast caps containing meat and a skeletal structure to obtain breast fillets therefrom, including: providing a mandrel having a plane of symmetry in vertical orientation; supporting a breast cap having a neck end and a tail end with its skeletal structure including a keel bone on top of the mandrel; holding the breast cap to the mandrel with the keel bone aligned with the plane of symmetry of the mandrel; moving the mandrel through a conveying path that extends through a substantially horizontal plane; providing a breast cutter in the conveying path; moving the mandrel through a conveying path in a direction of travel to pass the breast cutter for engagement with the meat along the keel bone; causing at least one incision to be provided along the area where the meat is attached to the keel bone; providing a breast fillet remover downstream of the breast cutter; allowing the breast fillet remover to engage between the skeletal structure on the mandrel and the meat; and separating the meat as a pair of single fillets from the skeletal structure, wherein the mandrel is being moved through the conveying path with the plane of symmetry aligned with the direction of travel, characterized in that the mandrel is moved through the conveying path with the neck end of the breast cap leading and the tail end trailing, and in that for enabling an optional step of de-skinning prior to moving the mandrel to pass the breast cutter, the mandrel within its plane of symmetry is brought into an upside-down position with the tail end of the breast cap leading for the optional step of de-skinning and is returned back again to its initial position prior to engagement of the meat with the breast cutter. providing a mandrel having a plane of symmetry in vertical orientation; supporting a breast cap having a neck end and a tail end with its skeletal structure including a keel bone on top of the mandrel; holding the breast cap to the mandrel with the keel bone aligned with the plane of symmetry of the mandrel; moving the mandrel through a conveying path that extends through a substantially horizontal plane; providing a breast cutter in the conveying path; moving the mandrel through a conveying path in a direction of travel to pass the breast cutter for engagement with the meat along the keel bone; causing at least one incision to be provided along the area where the meat is attached to the keel bone; providing a breast fillet remover downstream of the breast cutter; allowing the breast fillet remover to engage between the skeletal structure on the mandrel and the meat; and separating the meat as a pair of single fillets from the skeletal structure, wherein the mandrel is being moved through the conveying path with the plane of symmetry aligned with the direction of travel, characterized in that the mandrel is moved through the conveying path with the neck end of the breast cap leading and the tail end trailing, and in that for enabling an optional step of de-skinning prior to moving the mandrel to pass the breast cutter, the mandrel within its plane of symmetry is brought into an upside-down position with the tail end of the breast cap leading for the optional step of de-skinning and is returned back again to its initial position prior to engagement of the meat with the breast cutter.