Failure to take body height into considerations in the evaluation of nerve conduction velocities (CV) has recently been deemed unacceptable. This statement prompted the present study. Besides height, the influence of age, gender, and temperature was studied in 92 normal subjects, half of whom were females. The CV decreased 0.9 m/s per 10 years increase in age, the same in women and men aged 15 to 44 years. Mean temperature between distal and proximal ends of the nerve segment examined increased 6.1 +/- 0.3 degree C after heating followed by a CV increase of 7.0 +/- 0.5 m/s. The CV decreased 0.15 m/s per 100-mm increase in heights. When considering 37 individuals aged 25 to 34 years only, the CV increased 0.34 m/s per 1-m increase in height. In both instances, the changes were within the experimental error (2.3%) of the method.