Method and device for carrying out the method of mechanically harvesting inner and outer meat fillets from a poultry carcass breast cap. A poultry breast cap (23) is conveyed while being supported inversed to its natural position on a carrier (17) through a path of conveyance (25). The outer fillet is cut along a keel bone of the poultry breast cap (23) to enable separation of the inner and outer fillets. After separation and successive harvesting of the outer and inner breast fillets the carcass remains are discarded. The device (1, 13) for carrying out the method comprises means (15, 17, 29, 31, 33, 35, 37, 39, 41, 43) for performing at least the steps of conveying, separating and harvesting inner and outer breast fillets, and discarding carcass remains.