Abstract: Helicopter rotor blades require tip weights for spanwise and chordwise bace to assure that all of the blades rotate in the same track. The improved rotor blade tip weight assembly of the present invention comprises an elongated spar, preferably formed of a reinforced plastic, adapted to be connected at one end thereof to a rotor hub. An aft fairing structure is carried by the spar and a balancing weight assembly is bonded and/or cured in place within the spar, proximate the free end thereof. The balancing weight assembly includes, in the preferred form thereof, a fiberglass weight tube housing having a pair of internally threaded weight tubes positioned therewithin. The weight tubes form bores having longitudinal axes in a common, substantially horizontal plane, and the axes each extend in a direction parallel to the axis of the spar. One or a plurality of externally threaded cylindrical weights are locked in each weight tube during balancing of the rotor blade.