A new apparatus to meet 3 requirements was designed to measure a person''s ability to maintain steady balance while standing on an unstable platform, to present a real challenge to the person''s balancing ability, to be duplicable in other laboratories and to give an objective score easily read from an electric counter. The platform was balanced on a universal joint by 4 extension springs with sufficient tension to give opt. difficulty of the task. A hinged stylus which moved over a contact-target was in circuit with an interrupter (5 times/sec.) and an electric counter. A perfect score was 300/min. In 321 college [male][male] and [female][female] tested the highest score was 94%, the lowest 10%. There was a fairly high negative correlation between balancing score and weight (r =[long dash].70 and[long dash].82). Considerable variability occurred for the various wt. groups. Extended series of trials showed an average gain of about 7% due to learning. Correlations of successive trials were from .80to .85.