This study was undertaken to determine the relationship between quadriceps strength and balance to falls of institutionalized elderly people. The subjects comprised 25 elderly women aged 75.3 ± 3.4 years. The values of the postural sway in two standing positions, functional reach test, and quadriceps strength were compared between two groups of elderly adults, those with or without a history of fall. Quadriceps strength was measured using isometric contraction of the knee extension. There were no significant differences between the two groups in the postural sway in the two standing positions and the functional reach test. Quadriceps strength in the non-fall group was, however, significantly higher than that in the fall group (1.48 Nm/kg vs. 1.08 Nm/kg, p<0.01). The discriminating criterion for muscle strength between the two groups was 1.28 Nm/kg, with an apparent error rate of 24.8%. These findings suggest that (1) the degree of quadriceps strength may be a useful indicator for the prospect of fall in institutionalized elderly people, and (2) quadriceps strength should be maintained at least more than 1.28 Nm/kg to prevent fall.