Many forms of industrial illness are thought to result from the effects of vibration on the human body. Prolonged exposure causes undue stress and discomfort. At the human whole-body resonant frequency there is maximum displacement between the organs and the skeletal structure and thus this is one frequency of vibration that should be minimized in the workplace and elsewhere. The vertical whole-body resonant frequencies of 113 fully-clothed standing humans were measured using a vibrating beam method, which imposed a very low acceleration magnitude at the subjects' feet. The overall range of resonant frequencies was found to be from 9 to 16 Hz and independent of mass, height and mass to height ratio. The mean values (±1 s.e.) were 12·2±·1 Hz for males and 12·8±·2 Hz for females with an overall mean population value of 12·3±·1 Hz.