The invention relates to a machine tool for machining toothing of work pieces, comprising a rotating holding device (3) which can be rotated about a main axis A, two work piece spindles (4a, 4b) which are arranged on the rotating holding device (3), said work piece spindles (4a, 4b) comprising spindle axes (Sa, Sb) which are parallel to the main axis, in particular, the workpiece spindles (4a, 4b) being arranged symmetrically about the main axis A. Said machine tool also comprises a work tool holder (5) for the work tool (50) for machining a work piece (6) on one of the work piece spindles (4a). The invention is characterised in that the main axis A of the rotating holding device (3) extends in a horizontal manner. Soiling of the rotating holding device and work spindles can be reduced by separated chips and the constructive effort for a relative forward displacement of the work tool in relation to the work piece parallel to the spindle axes is reduced.