The invention relates to a chipper knife for chippers of the type comprising a tool (12) which is rotatable on an axis of rotation and is in the form of, for example a drum, disc or truncated conical body, which supports a plurality of such chipper knives. The chipper knife comprises at least one cutting edge (1) which is formed between a flank (2, 2') and a chip guiding surface (4, 4'), and two opposite main surfaces (3, 3') which are adapted to abut against and be retained on the opposite seats (14, 15) of a holder (9, 10) on the tool. At least one main surface (3, 3') of the chipper knife which is located on a wood side of the chipper knife comprises a cross-sectionally convexly bent surface portion (6, 5') which connects to and extends backwards from the flank (2, 2') and the chord of which constitutes at least 20 %, preferably at least 30 % and, most preferably, at least 40 % of the total cross-sectional length of the chipper knife. The invention also relates to a holder for such a chipper knife.