The strength of sensations caused by hand-transmitted vibration depend on the frequency and the magnitude of the vibration. Absolute perception thresholds, and the dependence of discomfort on vibration frequency (8 to 400 Hz) and vibration magnitude (0.16 to 99 ms^-2 r.m.s. and 0.002 to 0.126 ms^-1 r.m.s.), were determined for vertical vibration with a handle-grasping posture. The perception thresholds depended on vibration frequency with a U-shaped contour showing greatest sensitivity to acceleration around 125 Hz. The frequency-dependence of equivalent comfort contours strongly depended on vibration magnitude. At the higher vibration magnitudes investigated (greater than about 2 ms^-2 r.m.s.), the equivalent comfort contours were consistent with frequency weighting W_h as used in current standards for evaluating hand-transmitted vibration. At low vibration magnitudes, the shapes of the comfort contours were not the same as the reciprocal of the W_h frequency weighting. The results are partly explained by the receptor characteristics of the Pacinian and non-Pacinian systems in the glabrous skin of the hand.