Abstract: A two-spindle machine tool having a fixed first headstock with a main spindle extending in a direction Z and with a chuck, and two tool heads with turrets further has a movable second headstock with a main spindle extending in the direction Z and with a chuck, the second headstock and the two tool heads being supported on respective slide mechanisms which enable them to move in the direction Z and also in a direction X perpendicular thereto relative to the first headstock, and which are so positioned as to enable the two headstocks and two tool heads to function in respective operational regions enabling machining tools held by the turrets to perform various modes of machining including independent but simultaneous machining of respective workpieces held in the two chucks and simultaneous or successive machining of a single workpiece held by either of the chucks.