The CA-6000 Spine Motion analyzer was used to measure the lumbar spine's range of motion (ROM). One hundred and four asymptomatic volunteers were examined to obtain normal values for flexion/extension, lateral bending, and axial rotation. A detailed error analysis was conducted to investigate the inter- and intraobserver reliability of the measurement equipment, the differences between passive and active examination, the effects of stretching exercises before examination, and the diurnal changes related to lumbar spine ROM. Subjects were divided into groups by age and gender. Values for each group were compared with respect to age and gender. The measurements were found to be consistent and repeatable. Stretching exercises were observed to increase ROM. Passive examination was recommended to achieve maximum ROM. ROM was observed to increase during the course of the day. A normative database was established showing significantly decreased motion as age increased, but no gender differences were discovered. The validity of the axial rotation values due to fixation difficulties is questioned.