This paper describes recent developments in the flexible rotor balancing technology area, with particular emphasis on methods for the addition and removal of correction weights. The currently existing Multiplane-Multispeed Balancing procedure permits one-step balancing of final shaft-bearing assemblies simultaneously in a number of planes and at a number of speeds. Temporary addition of trial weights to the rotor, and the addition or subtraction of permanent corrections, are presently performed manually in the balancing process. The addition of a computer-controlled laser device to the balancing system shows promise of eliminating direct operator contact with the rotor in the balancing process, and thus could provide a considerable increase in the precision level at a critical step in the procedure. Preliminary investigations show that design-incorporated provision of suitably-located balancing planes on the rotor, and access to those planes from outside the machine casing through portholes, should permit balancing of machine rotors in place. Check-balancing of rotors without the need for stopping the rotor appears feasible.