[Purpose] The purpose of this study was to determine the effects of lumbar joint mobilization on the joint position sense (JPS) of normal adults. [Subjects] A total of 30 normal adults were divided into an experimental group (n = 15) and a control group (n = 15). [Methods] The experimental group received lumbar joint mobilization and massage, and the control group received massage only. Both the experimental and control groups were evaluated for joint position error (JPE) by using a digital dual inclinometer before and after the experiment. [Results] In the before and after comparison for the experimental group, statistically significant differences were found in flexion, extension, left lateral flexion, and right lateral flexion. There was no statistically significant difference in the before and after comparison for the control group. [Conclusion] Because lumbar joint mobilization can reduce JPE and improve JPS, its use in the treatment of patients with lumbar problems is recommended.