Background: People who have painful neck have reduced proprioception in the neck. Reduced proprioception in the neck is related to the muscle spindle activity in the deep neck flexors. The aim of this study was to know that proprioception in the neck was increased by strengthening exercise of the deep neck flexors. Methods: Thirty subjects with chronic neck pain were randomly assigned to the experimental group (n=15) and the control group (n=15). Deep neck flexor muscle exercise with stabilizer were conducted for the study group three times a week for six weeks. Relocation errors in 30 degree rotation to the left were measured three times before and after intervention each. Results: Neck disability index were decreased in the experimental group (p<.05) but not in the control group (p>.05). Relocation errors were decreased in the experimental group after intervention (p<.05), but not in the control group (p>.05). Conclusions: Proprioception in the neck can be increased by the strengthening exercise of deep neck flexors in the subject with chronic neck pain.